Rangers Starting Kumar Rocker Runs Against Grain of His Opener Success

The Texas Rangers left their Saturday and Sunday rotation spots open going into Friday’s game. But, during pre-game, manager Skip Schumaker filled one of them.

Schumaker told beat writers in Toronto, including The Dallas Morning News (subscription required) that the Rangers would start right-hander Kumar Rocker in Sunday’s game, leaving the Saturday start to be determined.

For the second time this season, the Rangers will start Rocker the game after he pitched successfully behind an opener. The data says the Rangers should reconsider.

Kumar Rocker With and Without an Opener

Rocker worked behind an opener on Monday in Miami, as he pitched five innings after a perfect first by reliever Tyler Alexander. The pair worked in a tandem on May 19 at Colorado and Rocker, as he did on Monday, looked more comfortable after Alexander, a left-hander, took the first inning.

The sample is limited, but the data shows it’s worked. In two games with an opener Rocker is 1-0 with a 1.42 ERA in 12.2 innings. He’s allowed nine hits and three walks with 16 strikeouts.

It’s not a perfect system. After all, it burns Alexander for a day, one of the Rangers’ more trusted relievers. But if the name of the game is winning games, the Rangers are 2-0 when Rocker pitches behind an opener.

Now, compare that to Rocker, the starter. While’s he’s a better pitcher at home, his overall line is 1-6 with a 4.70 ERA in 13 starts. He’s struck out 49, walked 27 and given up 32 earned runs in 61.1 innings.

Dig in further and there are other revealing numbers. For instance, his strikeout rate per nine innings for his starts is 7.2. For his two relief appearances its 11.4. His strikeout-to-walk ratio in his starts is 1.81 and in his two relief appearances its 5.33.

If the name of the game is winning games, the Rangers have done that with Alexander pitching in front of Rocker. This says little about Rocker’s long-term trajectory. It says more about where he is now. He’s having issues in the first inning — as are most of the Rangers’ starters this year — and entering the game in the second inning seems to do something to settle him down.

Is there a potential for diminishing returns eventually? Sure. Could Rocker get, well, rocked, if the opener has a bad first inning? That could also be true. But Texas remains under .500 and locked in a race with a host of teams trying to assert themselves in a middling American League playoff race.

If using an opener for Rocker in the short term keeps working, then the Rangers should keep doing it until it doesn’t work.

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