Houston Astros: A new way to use starting rotation is not needed

Should the Houston Astros limit starters to six innings?

Mike Petriello wrote a column for MLB.com today about the changing roles of pitchers. He says, “rather than looking at the first pitcher as ‘the starter, who has to get me through seven innings,’ teams ought to simply think about 27 outs and how best to get them.” Petriello uses OBP (on-base plus slugging percentage) and the rise in that particular stat as the starter goes through the batting order multiple times to conclude that “your starter facing more than 15-18 batters” can prove to be costing your team wins.

However, with three starters in the Houston Astros rotation, 2015 Cy Young Award winner Dallas Keuchel, 19 game winner Collin McHugh, and rookie sensation Lance McCullers, prove that this idea by Petrello may not be the best for this team.

In 2015, Keuchel pitched remarkably leading the American League with 20 wins while pitching 232 innings. He also posted a 2.48 ERA while leading the AL with a 1.017 WHIP (Walks and Hits per Innings Pitched). One of the reasons why Keuchel was so successful this season was because he adjusted to hitters as the game went on. Stats from Baseball-Reference.

The OPS of opposing hitters fell from .610 in their first plate appearance against him to a .553 in their third plate appearance. In batters’ second plate appearance against Keuchel, they hit a measly .199 with a BABIP (Batting Average On Balls In Play) of .244. This shows the effectiveness of his sinker, which causes Keuchel to get 61.7% ground balls in comparison to 19.6% fly balls on balls in play.

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Petriello did say in his article that this did not apply to the aces of the pitching staff. However, the two other examples in the Astros rotation, McHugh and McCullers prove to be against his way of thinking too. For example, McHugh actually struggles the most when facing an opponent the first time around with a .840 OPS and a .387 BABIP.

As the game goes on, however, McHugh begins to adjust and brings his OPS down to .640 and .660 respectively for the next two plate appearances. His batting average against falls dramatically also from .310 in the first plate appearance to the .240s for the next two.

For McCullers, he is actually at his best in opponents’ third plate appearance against him. Batters only hit .179 against him and have an OPS of .564. For pitch counts between pitches 51 and 75, hitters only bat .189 against McCullers and have an OPS of .538.

Next: Houston Astros 2015 Season Recap: Lance McCullers

For the three mainstays in this starting rotation, they seem to get stronger as the game goes on which is opposite to Petriello’s theory. The AL may be the first league to try something new with starting pitchers because of the luxury of the designated hitter, but if A.J. Hinch can use his starting rotation the way he wants, the stats say that he should use his starters the way that the MLB has adopted for the past 35 years.