Series Preview: Mariners (37-22) at Astros (37-24)

The month of May went about as well as it could have for the Mariners. The only missteps might have been the series loss to the Tigers on the road or the series split against the Rangers at home. But sweeping the Twins and the Rays made up for those two tough-luck losses. As a result, the Mariners enter play today a game ahead of the Astros, leading the AL West. Now comes the hard part: the next nineteen games include these two games in Houston, seven against the Red Sox, and three against the Yankees. Ideally, the Mariners would come out of this stretch with a 10-9 record. But even if they win just seven or eight of these nineteen games, they’ve already given themselves an excellent cushion thanks to a 15-5 record over their last 20 games.

The current standings in the AL West reflect both the soft schedule for the Mariners in May and a grueling month for the Astros. They faced the Yankees and Cleveland twice in May, plus the Red Sox and the Diamondbacks as well. They’ve won just four of their last 10 games.

Their championship run last season was built on a historically potent offense. By wRC+, the Astros offense was the best since the 1976 Reds. This year, their pitching staff is on pace for a historic season. They’re allowing just 2.9 runs per game, and if the season ended today, their park and league adjusted ERA and FIP would best the records set by Cleveland’s pitching staff last year. Their starting rotation has accumulated 9.9 fWAR already. Their bullpen has had a few meltdowns recently—their closer Ken Giles has carried his postseason struggles into this season—but they’re mostly byproducts of bad luck rather than bad pitching.

A historically great season is almost impossible to follow up, even with the bulk of the lineup carrying over from last year. José Altuve and Carlos Correa have been merely great rather than the elite offensive forces they were a year ago. Marwin González has taken a huge step back after his breakout year. And Josh Reddick and Brian McCann have both been sidelined with injuries. Still, the top half of their lineup is as good as any in baseball and should be able to carry the team until they get healthy or some of their veterans turn their seasons around.

Probable Pitchers

Since winning the Cy Young in 2015, Dallas Keuchel has posted back-to-back seasons with a FIP around 3.80. A spate of injuries have limited his effectiveness and have kept him off the mound for significant portions of the last two years. Still, he’s one of the best contact managers in the game, as evidenced by his 66.8% ground ball rate last season, easily the highest in the majors for a starter. He limits his repertoire to just his sinker and slider against left-handed batters but that’s clearly enough—they hit just .144 off him last season. To right-handed batters, he’ll also mix in a cutter and a changeup. His changeup is another plus pitch he can call on but his cutter just isn’t that great.

Keuchel has settled in right around that 3.90 FIP range this season. He’s generating the lowest ground ball rate since his rookie year and that’s mainly due to an increase in cutters and four-seam fastballs at the expense of his changeup and sinker. I’m not sure why Keuchel is moving away from his two best pitches, perhaps he’s trying to avoid the league trend towards better low-ball hitters. Whatever the reason behind it, he’s allowing the hardest contact of his career without a corresponding bump in strikeout rate.

Lance McCullers was the poster boy for the new, breaking-ball heavy approach popularized by the Astros pitching staff the past few years, but he’s a new man this season. After throwing his curveball over half the time the past few seasons, he’s started using his changeup much more often this year. As I wrote on FanGraphs last month:

“Because his curveball is so outstanding, his changeup has always been an afterthought. But during his career, he’s generated a whiff around a third of the time a batter swings at his changeup. And when batters do make contact, they put it on the ground more than half the time. Both of those marks are better than the average changeup, making it pretty effective.

A reliable third pitch should help McCullers navigate the opposing batting order later in the game. He’s really struggled when facing a lineup three or more times during his career. For the first two trips through the batting order, McCullers has posted an ERA of 2.97. That balloons to 5.50 when facing the order three or more times. In his four starts in May since reintroducing his changeup, McCullers has allowed just one run when facing the batting order the third time through (1.59 ERA).”

The Big Picture:

The Angels managed to narrowly win their series against the Rangers over the weekend. They started a three-game series against the Royals yesterday with a win. Oakland won their own series in Kansas City and will travel to Arlington to take on the Rangers this week. The Yankees split a doubleheader against the Tigers yesterday and travel to Toronto this afternoon for a three-game series.