It’s also possible the Astros win-loss record isn’t a true reflection of how good this team is. Based on their Pythagorean win percentage, which uses a team’s runs scored and allowed to derive how many games a team should win and lose, a team like Houston, which has 412 runs scored and 246 runs allowed, would be expected to have a 58-22 record, six more wins than they have heading into Tuesday night’s games. Take things a step further and use the Astros’ BaseRuns win percentage, a third-order winning percentage which takes into account a team’s performance without considering the sequencing to calculate expected runs scored and runs allowed, and Houston should be 54-26 based on its plus-166 run differential, which is also the best in baseball. The Boston Red Sox, by comparison, are second (plus-112) and the Yankees are third (plus-102), showing just how dominant the Astros have been in the early goings of 2018.
Run differential is simply the difference in runs scored versus runs allowed throughout the season. It’s not a perfect barometer of a team’s strength, but it does provide a good idea of which teams are winning decisively and which are squeaking by. And Houston, by outscoring opponents by over two runs a game, is on pace to be the most dominating team in since the introduction of the designated hitter in 1973. Since that time, no team has ever finished the season with a run differential per game higher than the 1998 New York Yankees, a team that averaged 1.91 runs more per game than their opponents. The 2001 Seattle Mariners (1.85) and 1995 Cleveland Indians (1.62) are second and third, respectively. If Houston can keep the momentum going, it will have accomplished something extraordinary.
And there is no reason to expect a slowdown anytime soon. Based on the team’s exit velocity and launch angle of balls put in play, the Astros are performing almost exactly as we would expect them to. Their expected batting average (.257) is not much lower than how they are actually performing at the plate (.264) and neither is their slugging percentage (.435 actual vs. 434 expected). Houston also doesn’t strike out often (20 percent, fourth-best) nor does it, as a team, chase many pitches out of the strike zone.
Second baseman Jose Altuve, the reigning AL MVP, leads the league in batting average (.343) with an .892 OPS, 55 percent higher than average after adjusting for league and park effects. His overall stats have taken a dip from last season, but based on his quality of contact and how hard he is hitting the ball, Altuve has room to improve. For example, players with his average exit velocity (88.6 mph) and launch angle (11 degrees) are expected to produce a slugging rate of .523, higher than Altuve’s actual rate of .491.
It’s unlikely the entire pitching staff can maintain its league-low 2.85 ERA, but even after adjusting that for league average results on balls in play and league average timing, also known as Fielding Independent Pitching, they would still have the lowest FIP in the majors this year (3.15), with an expected FIP — which replaces a pitcher’s home run total with an estimate of how many home runs they should have allowed given the number of fly balls they surrendered while assuming a league average home run to flyball percentage — not much higher (3.25). In other words, this is no fluke: Justin Verlander, Gerrit Cole, Lance McCullers Jr. and Charlie Morton are every bit as good as their stats say they are.
Verlander has been particularly good, and the rejuvenation of his four-seam fastball has been a key to his success. His vertical release point on the pitch is higher and, as a result, it is generating more vertical movement. His strike rate on the pitch this season is 76 percent and 42 percent of those are called strikes, both career highs.
He’s also using his fastball more aggressively — over 63 percent of his four-seam fastballs are in the strike zone, eclipsing his previous career high of 53 percent set last season.
As you can see, the Astros are good and look every bit the part of a champion capable of defending their crown. According to FanGraphs, Houston has a 26 percent chance to win the 2018 World Series, almost the double the estimate for the Yankees (15 percent) and significantly higher than the Cleveland Indians (11 percent) and Dodgers (11 percent). And with room to improve, those projections might be a bit low.