Matt Wieters has an .841 OPS in 24 games this season. (Elsa/Getty Images)

The annual four-game, home-and-home set between the Nationals and Orioles always spawns buzz, but this matchup is more than a meeting of regional rivals; it is a matchup of teams with two of the best records in baseball.

The Nationals are 21-10 with wins in four of the past five games, a 12-4 record on the road and sit in first place in the National League. The Orioles are surpassing projections again at 20-10 — the second-best record in the American League. They’ve won four straight and are 11-3 at Camden Yards.

These are officially two separate two-game series, but we’ll group them together for our purposes. Here are three things to consider as the neighbors play two in Baltimore before two in the District.

WIETERS RETURNS TO CAMDEN

The Orioles drafted Matt Wieters fifth overall in the 2007 draft and groomed the catcher into a four-time all-star, success that coincided with the franchise’s turnaround at the beginning of the decade. But the Orioles let Wieters walk last winter, and he happened to land at the other end of the Baltimore-Washington Parkway, easily becoming the most prominent player to jump between the regional rivals.

Wieters signed with the Nationals a week into spring training, but has since settled in. Usually a slow starter at the plate, Wieters is batting .274 with an .841 OPS in 24 game. Behind the plate, he’s influencing pitching plans, including having Gio Gonzalez (3-0, 1.64 ERA) rely more on his curveball and getting Tanner Roark (3-1, 3.46) to elevate his fastball more often to change batters’ eye levels.

Meanwhile, Orioles catchers — Welington Castillo, Caleb Joseph and Francisco Pena —  had combined for a .650 OPS entering Sunday, though Castillo, Wieters’s replacement, has been limited to 17 games because of injury.

WHERE DOES TURNER FIT?

The Nationals have two choices: Keep Jacob Turner in the bullpen or plug him back into the starting rotation in the slot vacated by Joe Ross. Turner has proven capable of putting up zeros as a reliever — he’s thrown six straight scoreless innings — and he could be a valuable piece for the beleaguered relief corps.

But he’s also probably the club’s best chance at solidifying the final spot in the rotation. A former first-round pick, the 25-year-old Turner has a starter’s repertoire and limited the Rockies to three runs over six innings at Coors Field in his only start.

The Nationals’ other option for the rotation spot is A.J. Cole. Cole held the Phillies to one run across six innings Saturday, but there was plenty of loud contract and command trouble after he posted a 6.63 ERA in four starts for Class AAA Syracuse to start season. Washington will have to decide by Thursday, when the fifth start spot comes up again. The team hadn’t listed the game’s probable starter as of Sunday.

WHAT’S THE LATE-INNING HIERARCHY?

Without Shawn Kelley (illness and back) and Koda Glover (hip) since April 29, Dusty Baker has had to cobble together late-inning bullpen roles based on matchups and availability.

On Thursday, he gave the eighth to Matt Albers, and Enny Romero handled the ninth — with Joe Blanton allowing a home run in between — for the save. On Friday, he assigned the eighth to Romero and inserted Albers in the ninth to notch his first career save. On Saturday, Turner tossed two scoreless innings to finish off a win. And on Sunday, Albers was entrusted to get out of a jam in the eighth inning and allowed his first three runs of the season with one pitch.

Glover was eligible to come off the disabled list Saturday and said he was ready to, but Baker said Sunday he doesn’t expect the team to activate him during the four-game stretch against Baltimore because Glover still needs to throw a couple bullpen sessions. If that’s the case, Baker will have to continue to mix and match to get the final outs with his undermanned relief corps.

“It’s been difficult,” Baker said. “It’s been difficult since the beginning.”

SERIES PROBABLES

Monday: LHP Gio Gonzalez (3-0, 1.64 ERA) vs. RHP Kevin Gausman (1-3, 7.55)

Tuesday: RHP Max Scherzer (4-2, 2.66) vs. RHP Ubaldo Jimenez (1-1, 6.58)

Wednesday: RHP Stephen Strasburg (3-1, 2.66) vs. LHP Wade Miley (1-1, 2.27)

Thursday: TBD vs. RHP Dylan Bundy (5-1, 2.17)