With the first full month of the 2019 season in the books, the American League West is shaping up to be the most competitive division in Major League Baseball.

The Astros have a slight edge over the Mariners for the division lead. The Rangers remain steady at 14-15, only 3 1/2 games back. But overall, only 5 1/2 games separate Houston from the A’s, who at 14-19 are last in the division.

For one team to pull away, someone will have to step up. Perhaps a guy currently going through a slump picks things up, or a player returning from injury provides a boost. As we enter May, here’s a look at one player from each AL West team to keep an eye on this month:

Angels: Designated hitter/pitcher Shohei Ohtani

Ohtani is set to return in early May as a designated hitter after having Tommy John surgery on Oct. 1. The reigning AL Rookie of the Year should provide a huge boost to the Angels' lineup with his power and speed. There could be some early rust, as he’s skipping a rehab assignment to take part in simulated games instead, but there’s no doubt the Angels are excited to have him serve as their regular DH. -- Rhett Bollinger

Astros: Second baseman José Altuve

The top of the Astros' batting order is filled with star power, but the former AL Most Valuable Player Award winner is what makes the offense go. Altuve has been a little overeager at the plate lately, though he’s still drawing walks. The bar is so high that when he suffers a lull, he gets a little antsy and swings at pitches outside the strike zone that he can put in play, but not necessarily put in play well. Altuve has hit well on the road in his career, and May brings road series in Anaheim, Detroit and Boston. Altuve’s career OPS for May is .800, his lowest in a month outside of August and September. -- Brian McTaggart

Athletics: First baseman Matt Olson

The A’s lineup can hit home runs with the best of them -- it slugged 227 homers in 2018, good for third-most in the Majors. Oakland has hit 43 so far in 2019, still near the top of the league. But since April 12, the A's 11 home runs are the least of any team in baseball.

Enter Olson. The first baseman began his rehab assignment with Triple-A Las Vegas on Wednesday and he could be back as soon as Tuesday for the start of a six-game homestand. Of course, it will be nice to get Olson’s Gold Glove defense back, but perhaps even more importantly, the A’s will be glad to get his power back into the middle of the lineup. He slugged 29 home runs in his first full season last year, six of those coming in May. -- Martin Gallegos

Mariners: First baseman/DH Edwin Encarnacion

Since 2012, no player in the Majors has cranked more home runs and driven in more runs than the 36-year-old Encarnacion. He’s at it again this season for Seattle, on pace for 40 homers and 100 RBIs while posting a strong .376 on-base percentage after the first month for his new club.

But Encarnacion isn’t a long-term piece for a team looking to the future, which is why general manager Jerry Dipoto is open to moving the veteran and his $20 million contract. With Kyle Seager’s expected return from hand surgery in about a month likely to push Ryon Healy back to first base, Seattle is headed toward a logjam, with Encarnacion, Daniel Vogelbach and Jay Bruce already splitting time at first and designated hitter.

Encarnacion could increase his trade value with a strong May if he continues showing the ability to be a big-time run producer, after also showing he could play a decent first base for Seattle in April. -- Greg Johns

Rangers: Closer José Leclerc

Leclerc has an 8.44 ERA after his first 13 appearances. Over 10 2/3 innings, he's allowed 10 runs on 14 hits and nine walks, while striking out 14. He has just two blown saves in seven tries, but only because he was bailed out by Kyle Bird and Shawn Kelley in two others. His fastball command has been erratic, allowing hitters to sit on his offspeed stuff. Manager Chris Woodward has shown faith in Leclerc, but recently removed him from the closer role. If it's not going to be a permanent change, Leclerc needs to pitch better. -- T.R. Sullivan