The Astros are rolling, but they have close company in the American League West, with the Angels and Mariners keeping pace through the first quarter of the 2018 season.
The A's are putting up a fight, rallying to stay in the mix, while the Rangers are lagging at the bottom. Here's a peek at how each club has fared thus far, with a look ahead at what's next:
Angels
One thing we learned in the first quarter:Shohei Ohtani is the real deal. The two-way phenom has logged a 3.58 ERA with 43 strikeouts over 32 2/3 innings as a right-handed pitcher while batting .342 with a 1.015 OPS and five home runs as a left-handed slugger. His proficiency in both disciplines even led the Twins' Logan Morrison to describe him as "probably the best player in the world." The Angels have been conservative with Ohtani's workload thus far, but they're hoping he'll eventually be able to pitch more frequently later this season, which could allow him to make an even greater impact.
One thing we'll be watching in the second quarter: Will the Angels' bullpen hold up after a heavy April workload and injuries? The Angels leaned heavily on their relievers in the first month of the season and then saw Blake Wood and Keynan Middleton land on the disabled list. Middleton, who has a damaged ulnar collateral ligament in his right elbow, will likely miss significant time, leaving a hole at the back end of the bullpen. The Angels will try to fill the void by using a closer-by-committee approach, with rookie Justin Anderson, Jim Johnson and Cam Bedrosian potentially factoring into the ninth-inning mix. If the unit doesn't stabilize, the Angels could be prompted to look externally for relief help.
Key series or stretch of schedule: May 25-27 in New York and June 26-28 in Boston. The Angels went 0-6 against the Yankees and Red Sox at Angel Stadium in April, but they'll have another chance to test themselves against two of the AL's best teams in the second quarter of the season.
Stock watch: Now that their starting rotation has gotten back on track, the Angels seem to be trending up. They are two games behind the Astros in the AL West standings, and they have the potential to challenge the defending World Series champions for the division title if everything breaks right.

Astros
One thing we learned in the first quarter: Houston's starting pitching has a chance to be historically great. Houston's starters, through 45 games, have a 2.24 ERA, which is tops in the Major Leagues by more than half a run. Gerrit Cole and Justin Verlander are making early AL Cy Young Award cases, and Charlie Morton is picking up where he left off last year. Meanwhile, Dallas Keuchel and Lance McCullers have also pitched well. Starting pitching is why the Astros are near the top of the division.
One thing we'll be watching in the second quarter: The offense. Houston led the Majors in runs scored, batting average and just about every other offensive category last year (it was second in homers). The Astros, who had the fewest strikeouts in the big leagues last year, are striking out more and chasing more pitches, which has led to a spotty, inconsistent offense. The Astros need elite performances from Carlos Correa, George Springer and Jose Altuve, but Josh Reddick and Alex Bregman can find another gear as well. Production in left field and at designated hitter has been poor. Will Astros No. 2 prospect Kyle Tucker, an outfielder, be up in June?
Key series or stretch of schedule: In 16 games from Friday through June 3, the Astros play the Indians seven times (three in Houston, four in Cleveland), the Yankees three times on the road and the Red Sox four times at home in their biggest tests to date.
Stock watch: The Astros are steady. They've been in first place or near the top of the AL West for most of the season, thanks to their pitching. Still, they're not playing at the championship level of a year ago because the offense hasn't produced up to its capability.

Athletics
One thing we learned in the first quarter: The A's are only as good as their starting staff, which has already undergone quite the makeover since the season's start. Opening Day starter Kendall Graveman is in Triple-A, and veterans Trevor Cahill and Brett Anderson are back in the A's rotation for the first time since 2011. It's an odd ensemble, now led by Sean Manaea, and it's been their weakest link to this point.
One thing we'll be watching in the second quarter:Matt Olson and Matt Chapman endured their shares of struggles in the first quarter, but the corner-infield duo has shown signs of life at the plate of late. The A's pride themselves in a deep lineup, not wanting to rely on just one or two bats on any given day, but getting Olson and Chapman going would go a long way toward keeping the offense afloat.
Key series or stretch of schedule: Following a challenging stretch in the schedule, the A's will return to Oakland on Tuesday and play 20 of their next 25 games within the comforts of the Coliseum. Taking advantage of this will be crucial for them.
Stock watch: The A's are steady and hanging around .500, which is a respectable showing for a young club, but they'll need to produce on both sides of the ball more consistently should they want to remain competitive in a tough division. It's still early, and the second quarter will help dictate how they proceed ahead of the July 31 non-waiver Trade Deadline.

Mariners
One thing we learned in the first quarter: The Mariners have the offense to make a push and have stayed close on the heels of the Astros and Angels thanks to their most balanced lineup in years. Dee Gordon's speed has been a difference-maker, and if Seattle gets sufficient help from its rotation, this is a club that could make some noise.
One thing we'll be watching in the second quarter: A broken bone in his hand and then an 80-game suspension for Robinson Cano sent shock waves through the club on Tuesday. Cano's absence leaves a large void both in the lineup and the clubhouse. Gordon will move to second base from center field shortly, but Cano's bat won't be easily replaced in the No. 3 spot in the order. How the Mariners handle the loss of the eight-time All-Star will be crucial to their season's chances since he won't return until mid-August.
Key series or stretch of schedule: After a road-heavy start, the Mariners just began a stretch with 16 of 19 games at Safeco Field, all against sub-.500 teams. A hot stretch now would set up an interesting June, where the schedule toughens with a big homestand against the Angels and Red Sox before hitting a 10-day trek to the Bronx, Boston and Baltimore.
Stock watch: The Mariners are faring much better than most expected, so their first-quarter stock is definitely up. But how they adjust to playing without Cano figures to determine how good they can be in the second quarter.

Rangers
One thing we learned in the first quarter: The Rangers' offense continues to be crippled by strikeouts and a lack of hitting with runners in scoring position. Their bullpen has been in a state of flux, although Keone Kela has seized the closer's role. But the biggest thing gleaned from the first quarter is the Rangers' starting pitching continues to struggle. Through 44 games, their starters are a combined 11-19 with a 5.14 ERA and a 1.46 WHIP. They also average 5.4 innings per start.
One thing we'll be watching in the second quarter: The Rangers need Joey Gallo to get hot. He has 13 home runs but is hitting just .200 with a .281 on-base percentage. The home runs are nice, but Gallo showed in the second half of last season that there is more to his game than just that.

Key series or stretch of schedule: From May 28 through June 10, the Rangers play 13 straight games against their four division opponents. The stretch starts with a road trip of four games in Seattle and three in Anaheim. That's followed by a six-game homestand -- two against the Athletics and four against the Astros at Globe Life Park. That may be their best chance to get back in the division race.
Stock watch: The team's stock is down, but a couple of their players are definitely trending up. Nomar Mazara is turning into an All-Star player. He is hitting .279 with a .335 on-base percentage and a .509 slugging percentage. Right now, he is the Rangers' best candidate to represent them at the All-Star Game. Delino DeShields has left little doubt about his ability to lead off and play center field.