Now that we’re more than a month into the 2024 season, the sample size is becoming large enough for narratives to form around certain teams. Some of the teams who were supposed to be successful have indeed been successful, with the Orioles and Yankees among them. But there have certainly been some surprises as well -- are the Royals this good? Are the Astros this bad?

Those four teams are among several that will take the field in notable series this week, including two of those teams facing each other. Here are five key series to watch during the week of May 6.

Rangers (19-16) at Athletics (17-18)
4 games (Monday-Wednesday, doubleheader Wednesday)

Head to head: The A’s took two of three games against the Rangers in Texas in April. Last season, the Rangers went 9-4 against the A’s -- tied for their most wins against any team en route to their World Series title (also won nine against Seattle).

Storyline: Will either team surge to the top in the AL West? Much thanks to Houston’s surprising struggles (more on that below), the division is extremely wide open, as it’s the only division without a 20-win team. The Mariners currently lead with a 19-15 record, but every team is within striking distance, including these two.

Watch out for: JP Sears. Last time these two teams faced off, Sears was stellar, taking a no-hit bid into the seventh inning and finishing with 6 1/3 innings of one-hit ball in a 1-0 win. Sears is projected to take the mound against the talented Rangers lineup during Wednesday's first game.

Brewers (20-13) at Royals (20-15)
3 games (Monday-Wednesday)

Head to head: These two teams have not faced off yet this season. In 2023, the Brewers swept the Royals in three games played in Milwaukee in May.

Storyline: How real are the Royals? Last season, Kansas City finished 56-106, the second-worst record in MLB ahead of only Oakland’s 50-112. This year, thanks to a stellar pitching staff (3.34 runs allowed per game, second-fewest behind Seattle), the Royals find themselves in playoff position as it stands now. On the flip side, the Brewers lead the NL Central, which they also won in 2021 and 2023.

Watch out for: Salvador Perez. In his 13th MLB season, the 34-year-old catcher has remarkably discovered the fountain of youth, holding a .328 batting average and .954 OPS that both lead the Royals. The advanced metrics suggest that Perez’s output could be here to stay, as he ranks near the top of the sport in a plethora of Statcast hitting metrics.

Mariners (19-15) at Twins (19-14)
4 games (Monday-Thursday)

Head to head: These teams have not yet played each other this season. In 2023, the Mariners went 4-3 against the Twins, including a 2-1 record in Minnesota in July.

Storyline: How real was the Twins’ win streak? Minnesota’s 9-2 loss to the Red Sox on Sunday snapped a 12-game win streak -- the longest for the franchise since its most recent World Series-winning season in 1991. Are the Twins closer to the team that won 12 in a row, or the team that was 7-13 before that? As another storyline, can two-time reigning All-Star Julio Rodríguez get back on track in his third season with Seattle (career-low .313 slugging percentage)?

Watch out for: Ryan Jeffers. The 27-year-old was a relative unknown entering 2024, never having appeared in 100 games in a season. This year, in a combination of a DH role along with platooning catching duties with Christian Vázquez, Jeffers has excelled, leading all Twins qualified hitters with a .291 batting average and .938 OPS.

Astros (12-22) at Yankees (23-13)
3 games (Tuesday-Thursday)

Head to head: The Yankees swept the Astros in a four-game series to open the season in Houston, two of which were decided by one run. Notably, these teams have faced off in the ALCS three times since 2017, with the Astros winning all three (2017, ‘19, ‘22).

Storyline: What’s up with the Astros? Fresh off a record seventh consecutive ALCS appearance (one shy of the 1990s Braves' record of eight straight NLCS), Houston has not resembled that team to begin this season. Among the several issues plaguing the team is an MLB-worst 1-9 record in one-run games, including the aforementioned two losses to the Yankees in March.

Watch out for: Luis Gil. It’s hard to ask for a much better fifth starter than the 25-year-old rookie, who’s played a huge role in the Yankees’ pitching staff’s success. Gil didn’t start in the season-opening series in Houston, but his .138 expected batting average allowed leads all starting pitchers with at least 50 batters faced. He is projected to start on Tuesday.

D-backs (15-20) at Orioles (23-11)
3 games (Friday-Sunday)

Head to head: These two teams have not faced off in 2024. Last season, the Orioles took two out of three matchups in Arizona in September.

Storyline: Can Arizona snap out of the World Series runner-up hangover? Fresh off being arguably the most unlikely pennant winner in MLB history, 2024 has not gone nearly as smoothly, as a rash of pitching injuries have partially contributed to the team currently sitting in fourth in the NL West, only ahead of the lowly Rockies.

Watch out for: Colton Cowser. Though Jackson Holliday garnered more headlines entering the year, it’s Cowser who has been the biggest revelation among the Baltimore rookies. Cowser has a team-high .928 OPS (min. 90 PA), and his 19.6% barrel rate ranks third in MLB.