The Rangers’ New Ace?

Most baseball fans — even those who count themselves among the TMI readership — were probably a little surprised to find that someone named Colby Lewis had not only signed with the Texas Rangers this offseason, but was immediately considered a prime candidate for a starting rotation. If the name sounded somewhat familiar, it’s because Lewis entered 2010 with over 200 Major League innings under his belt, having made appearances at the highest level every year but one from 2002 to 2007. As for the quality of those innings, well, you be the judge.

In 217 innings, Lewis had a 6.71 ERA with 155 strikeouts with 124 walks. He was awful. But after a couple of years playing in Japan, he showed the kind of stuff that made him a supplemental first-round pick of the Rangers back in 1999, as he had eight strikeouts for every one walk while playing for Hiroshima.

Lewis’s numbers in Japan certainly impressed a couple of the projection systems we host at FanGraphs. Sean Smith’s CHONE projections call for Lewis to end 2010 with 167 innings, a 3.99 ERA, and a 1.13 WHIP. Dan Szymborski’s ZiPS projects Lewis for a 4.39 ERA in 176 innings. Not incredible, but still serviceable when one considers Lewis’s home ballpark (which ranks among the top-third of all parks in run inflation).

Yesterday’s start in Cleveland, however, might create even loftier expectations. Obviously, small sample size caveats abound here, but Lewis’s final line against the Indians was excellent. In 5 1/3 innings, he struck out 10, walked four, and allowed just two runs. Remarkably, those 10 whiffs came against just 24 batters faced, meaning Lewis fanned more than 40 percent of opposing batters.

Of particular note are the 15 swings-and-misses Lewis generated on the night. In a study published last summer, Jeff Sullivan of Lookout Landing finds that there is a great deal of correlation between swinging strikes and strikeout rates. Starting pitchers, on average, induce a swing and miss a little more than eight percent of the time. Last year’s strikeout leaders Tim Lincecum and Justin Verlander finished 2009 with swinging-strike rates of about 11 percent. Last night, Lewis managed to generate whiffs on a full 13 percent of his pitches.

Does this mean we can expect to find Lewis’s name among the list of strikeout leaders by year’s end? My guess is no. But he could still be a success without striking out 200 batters. In any case, his is a compelling story, and one that will be a pleasure to follow for the remainder of the 2010 season.