Cy Young winner Dallas Keuchel anchors an Astros rotation that finished second in the AL in ERA in 2015. (Jamie Squire/Getty Images)

Here is, maybe, the oddest thing about the American League West: Mike Trout is entering his fifth full major league season, and he has not won a single playoff game, advancing to the postseason only once.

The mystery of the Los Angeles Angels is just one theme that defines this division, and nearly every franchise in it has a similar question. What to make of Seattle, which headed into 2015 with lofty aspirations but now has a new general manager and new manager? How about Oakland, which followed up three straight postseason appearances with a 94-loss abomination? Is Texas really as good as its 37-21 finishing kick last year?

Which leaves us with Houston, the only team in the division with a decidedly upward trajectory. Four-hundred-sixteen losses from 2011-14? Pffffft. Here come the Astros.

Houston Astros

2015 record and finish: 86-76, second, lost to Kansas City in ALDS
2016 FanGraphs projection: 86-76, first
2016 Baseball Prospectus PECOTA projection: 88-74, first
Significant additions: RP Ken Giles, SP Doug Fister
Significant losses: SP Mark Appel, SP Scott Kazmir, IF Jed Lowrie, 1B Chris Carter, RP Chad Qualls, RP Oliver Perez, RP Joe Thatcher

Why they’ll win the division: A full season of Carlos Correa — and organizational depth

The Astros’ long, painful rebuild ended in 2015 when they clung to a second-place finish, earned a wild-card spot, beat the Yankees and nearly eliminated the Royals. Now, more is expected, and reasonably so. First off, they’ll have a full season — rather than just the 99 games he played as a rookie — of 21-year-old phenom Correa, whose .857 OPS led all shortstops with at least 400 plate appearances last year. One of the top prospects in the game, there’s no reason for a regression here. He should be the star around which the Astros are built for years, and 155 games of Correa will only add to an offense that was outscored by only five teams in 2015. The rotation is anchored by Cy Young winner Dallas Keuchel, whose 2.48 ERA over 232 innings helped the Astros rank second in the AL in rotation ERA. And the bullpen got its closer when General Manager Jeff Luhnow traded three pitching prospects to Philadelphia for Ken Giles, whose presence allows Luke Gregerson to pivot back into a setup role. Throw in the smart re-signing of stingy lefty Tony Sipp, and the Astros have strengths in the rotation, the bullpen and the lineup.

Most significant question: Where does Lance McCullers fit in a potentially deep rotation?

After Keuchel, Collin McHugh (who logged his first 200-inning season and was credited with 19 wins in 2015) and Mike Fiers (who threw a no-hitter as an Astro after being acquired from Milwaukee) are basically assured spots in the rotation. Scott Feldman is coming off a shoulder injury and bears watching, and Doug Fister could be one of the steals of the offseason (one year, $7 million) if the former National finds his 2014 form. McCullers, 22, is the most interesting element. Luhnow said the club will limit McCullers’s innings in 2016, but it appears that program will be designed to have him ready in October. But the reason he’s intriguing: His first 125 2/3 major league innings produced 129 strikeouts, a 3.22 ERA and a 1.186 WHIP. Watching him in spring, and deep into the season, could provide a clue as to how formidable Houston might be in the playoffs.

Spring training battle to watch: Jon Singleton vs. regular playing time

Before he had played a game in the majors, the Astros first baseman signed a five-year, $10 million contract that was criticized by some players and agents as being far too team friendly given Singleton’s enormous potential. Now, though, he’s coming off a pair of seasons in which he has played only 114 big league games and hit just .171 in them. But with Chris Carter departed to Milwaukee, first base would seem to be the 24-year-old’s to own. If not, Astros fans will surely clamor for A.J. Reed, the 2014 second-round pick who destroyed high-Class A and Class AA last year to the tune of 34 homers and 127 RBIs in 135 games.

Did you realize?: How much power the Astros have?

Only the Blue Jays hit more homers than Houston, and by just a 232 to 230 margin, and the power comes from all over the lineup. No Astro hit more than Evan Gattis’s 27 homers (and Gattis could miss the start of the season after hernia surgery), but Correa (22), Luis Valbuena (25), Colby Rasmus (25) and the now-departed Carter (24) were all north of 20, plus six other players reached double digits.

Texas Rangers

2015 record and finish: 88-74, won AL West, lost to Toronto in ALDS
2016 FanGraphs projection: 82-80, third
2016 Baseball Prospectus PECOTA projection: 80-82, third
Significant additions: SP A.J. Griffin, RP Tom Wilhelmsen, OF James Jones, OF Justin Ruggiano
Significant losses: SP Yovani Gallardo, 1B Mike Napoli, RP Anthony Bass, OF Leonys Martin, OF Drew Stubbs, OF Will Venable, RP Ross Ohlendorf

Most significant question: When will Yu Darvish return, and what will his contribution be?

That the Rangers won the division a year ago with exactly zero games pitched by their best pitcher is nothing short of remarkable. From 2012-14, his first three major league seasons, no AL starter struck out more batters per nine innings (11.22) or allowed a lower batting average against (.214). Yet he underwent Tommy John surgery in spring training of 2015 — and the Rangers sailed on without him. Now, he’s due back in mid-May, and he’ll have to replace the innings vacated by departed free agent Yovani Gallardo (184 1/3 at a 3.42 ERA).

Spring training battle to watch: Joey Gallo vs. contact.

The third base/left field prospect has enormous offensive upside, and the Rangers tried to take advantage last year by calling him up in June, when he was 21. He homered and drove in four runs in his major league debut, and he was supposed to be part of Texas’s push to the division title. But he struck out an incredible 43 times in 98 plate appearances before being sent back to the minors at the end of the month. He reappeared as a September call-up, but finished the year with 57 punch-outs in 123 plate appearances. Gallo has 127 homers and a .971 OPS in 383 minor league games over four seasons, but he must be able to put his bat on major league pitching more consistently in order to be a part of the Rangers’ 2016 run.

Did you realize?: Josh Hamilton is a shell of his former self.

When he signed a five-year, $125 million contract with the Angels following the 2012 season, Hamilton was coming off five straight all-star seasons with Texas, during which he hit .305 with a .912 OPS and won an MVP award. Yet after a relapse of substance abuse, the Angels gladly pedaled him back to Texas last April, and while Hamilton was the Rangers’ most frequent left fielder, there are questions as to whether he can ever retain his former levels. By the playoffs, he was buried in the Rangers’ order, and went just 3 for 18 in five games against the Blue Jays. Now, he’ll make $28.4 million this season — all but $2 million paid by the Angels — and must improve on a .253 average and .732 OPS with the Rangers a year ago.

Seattle Mariners

2015 record and finish: 76-86, fourth
2016 FanGraphs projection: 84-78, second
2016 Baseball Prospectus PECOTA projection: 84-78, second
Significant additions: GM Jerry Dipoto, Manager Scott Servais, 1B Adam Lind, SP Wade Miley, SP Nathan Karns, OF Nori Aoki, RP Joaquin Benoit, RP Steve Cishek, C Chris Iannetta, Steve Clevenger
Significant losses: GM Jack Zduriencik, Manager Lloyd McClendon, SS Brad Miller, 1B/DH Mark Trumbo, SP Roenis Elias, 1B Logan Morrison, RP Carson Smith, RP Tom Wilhelmsen, RP Joe Beimel

Most significant question: Did Robinson Cano’s second half mean the first was just a blip?

When the 2015 Mariners, who had World Series aspirations, got off to a sluggish start, Cano was an easy scapegoat because his .660 OPS didn’t match his $240 million contract. But the second baseman resurrected himself after the all-star break, hitting .331 (against .251 before the break) with a .387 on-base percentage and .551 slugging percentage that made him far and away the second baseman with the highest post-break OPS (.926). Still, the sum total left him with his lowest average, on-base percentage, slugging percentage and OPS since 2008. He is coming off core surgery at the end of last season. Will he be the old Cano, or is there need to revamp expectations of what he can and will be?

Spring training battle to watch: Taijuan Walker vs. Nathan Karns vs. James Paxton

Two of those pitchers will win spots in the rotation. The loser could end up in the bullpen. By far the most intriguing is Walker, who finally managed to stay in the majors for a full season (29 starts), but was woefully inconsistent while there. Walker allowed zero, one or two earned runs in 11 of his starts, but failed to complete six innings 10 times. For the Mariners to max out, their most talented pitching prospect must pitch to his ability. Karns arrived in the offseason trade that sent incumbent shortstop Brad Miller to Tampa, which opened the door for prospect

Did you realize?: Felix Hernandez went 18-9 with a 3.53 ERA in 2015 — and it was just about his worst season of his last seven.

Here is Hernandez on average from 2009-14: 2.73 ERA, 1.099 WHIP, 232 innings and 226 strikeouts per season. Last year marked his fewest innings (201 2/3), highest ERA, second-highest WHIP (1.180) and fewest strikeouts (190) since 2008.

Los Angeles Angels

2015 record and finish: 85-77, third
2016 FanGraphs projection: 81-81, fourth
2016 Baseball Prospectus PECOTA projection: 75-87, fourth
Significant additions: SS Andrelton Simmons, RP Al Alburquerque, IF Yunel Escobar, C Geovany Soto, OF/1B Daniel Nava, IF Cliff Pennington, GM Billy Eppler
Significant losses: SS Erick Aybar, 3B David Freese, OF Collin Cowgill, OF David DeJesus, C Chris Iannetta, RP Trevor Gott, IF Conor Gillaspie, OF Shane Victorino, OF David Murphy

Most significant question: Why didn’t they have a more active (read: expensive) offseason?

Jerry Dipoto resigned as general manager midseason, and Eppler, a former assistant to Brian Cashman with the Yankees, was hired as the permanent replacement after the year. The Angels have rarely shied from spending money, but with several free agents available who could have addressed their many needs — from outfielders Alex Gordon and Yoenis Cespedes to any number of starting pitchers — Los Angeles basically stayed out of the market. Yes, they made a wise trade for the slick-fielding Andrelton Simmons at short, and Yunel Escobar should be a solid replacement for David Freese at third (though whether he can replicate his 2015 season in Washington is an open question). But are those additions enough to bump up an offense that ranked 12th in the AL in runs scored and 14th in OPS?

Spring training battle to watch: Youth vs. experience in the rotation

Jered Weaver has been in the Angels’ rotation since 2006, C.J. Wilson since 2012. Each, though, is in the final year of his contract, and it feels like the guard is about to change. Not only has Garrett Richards, 27, established himself at the top of the rotation, but it appears that 24-year-old Andrew Heaney (3.49 ERA in 18 starts last year) is ready to join him. This will be a major part of the Angels’ evolution beyond this year: What will they get out of Weaver and Wilson in 2016, and how will they move on from them (if, indeed, they do) going forward?

Did you realize?: Mike Trout has played four major-league seasons and never finished lower than second in the MVP voting.

The Angels center fielder doesn’t turn 25 till August, but from 2012-15, his ranks in all of baseball: fourth in average (.308), second in on-base percentage (.403), second in slugging (.577), second in OPS (.986), first in wins above replacement (37.8, according to FanGraphs). And yet there’s reason to believe he’s being abandoned by the Angels, who aren’t surrounding him with enough support.

Oakland Athletics

2015 record and finish: 68-94, fifth
2016 FanGraphs projection: 79-83, fifth
2016 Baseball Prospectus PECOTA projection: 75-87, fifth
Significant additions: 1B Yonder Alonso, SP Rich Hill, SP Henderson Alvarez, RP Ryan Madson, RP Marc Rzepczynski, RP John Axford, RP Liam Hendriks
Significant losses: 3B Brett Lawrie, 1B Ike Davis, SP Jesse Chavez, RP Fernando Abad, RP Dan Otero, RP Pat Venditte

Most significant question: Can the bullpen be better, and will that make a significant difference in the record?

Oakland’s disastrous 2015 was anchored in its struggles to pitch in the late innings. The Athletics’ 4.63 ERA from their relievers was the worst in the AL a year ago, and they traded de facto closer Tyler Clippard midseason. So look at the overhaul General Manager Billy Beane orchestrated this winter: The major acquisitions for the A’s were bullpen veterans Ryan Madson, John Axford and lefty Marc Rzepczynski. Closer Sean Doolittle made just 12 appearances last year because of shoulder issues, but he is expected back healthy. Given the A’s were outscored by only 35 runs last year — not a number that would suggest 94 losses — some tightening up in the late innings could yield significant improvements.

Spring training battle to watch: Marcus Semien vs. groundballs.

The talented shortstop, acquired in last offseason’s trade for right-hander Jeff Samardzija, couldn’t shake an early-season case of fielding jitters and finished with 35 errors — not only the most in baseball by eight errors, but 13 more than the next-closest AL shortstop. This hindered an otherwise solid Oakland defense (the A’s ranked eighth in baseball in the advanced metric of defensive runs saved), and colored Semien’s entire season. But the A’s hired former Texas manager (and former Oakland coach) Ron Washington as a mentor midseason, and in 66 games from July 10 on Semien made just seven errors. He has offensive potential, as his 15 homers would indicate, and at 25 there’s still time to realize it if he can just make his defense a non-issue.

Did you realize?: How good Sonny Gray is?

Since he came up as a rookie in 2013, here are the American League starters with a better ERA than Gray (minimum, 450 innings pitched): Felix Hernandez (2.86 to 2.88). During that time, among AL pitchers, he ranks sixth in WHIP, first in batting average against (.221) and second in homers allowed per nine innings (0.66). One would think his spacious home ballpark would have something to do with that success, but Gray is actually better on the road (2.70 ERA and .587 OPS against away from home, 3.03 ERA and .619 OPS against in Oakland). Gray, too, will serve as an indicator of Oakland’s intentions: If the A’s hold onto him beyond the trade deadline, they may believe they can contend in 2017. But if they’re going into complete rebuild mode — as they did from 2007-11, when they didn’t have a winning season — they could deal Gray, who’s not even yet eligible for arbitration, for what would have to be a pile of prospects.