Daily Graphing – Twins’ Perfect Storm

By now everyone’s heard that Francisco Liriano has joined Minnesota’s rotation and will start Friday in place of Carlos Silva. Liriano has one of the highest ceilings of any pitching prospect and has shown that so far in 2006 he’s ready to live up to the hype. While Silva has been disastrous this year, the same can also be said for two other Twins’ pitchers: Brad Radke and Kyle Lohse. Which of these three starters really deserves to be banished from the rotation?

Radke is the only one of the three whose ERA fits on the graph below, and it’s still over 7.00. Over the past few years Silva has the best track-record, with Radke about league-average and Lohse slightly worse than that. Based on past ERA and age, Silva looks like the best bet to lower his ERA.

If we dig deeper, however, that’s not really the case. Silva has been walking a fine line for the past few years, striking out an amazingly low 3.4 hitters per 9 innings in both 2004 and 2005. In fact, all three pitchers struggle to accumulate free outs, and except for Lohse’s 2006 data point, all three are riding downward trends.

The other thing a pitcher has direct control over other than strikeouts is walks. Silva’s success in 2005 can be attributed to a historically low .43 BB/9; he walked only 9 batters in 188 innings! Radke is also considered a control specialist, and Lohse is above average as well. Is it any surprise that all three pitchers have seen an increase in their walk-rates this season?

You’ve seen the bad. Here comes the ugly. None of these three pitchers allowed homeruns at a better than average rate in 2005, but they might as well let opposing batters hit off a tee this year. Lohse is the only one of the three whose data point appears on the graph. He’s giving up about 1.5 HR/9 which still falls into the poor category. Radke is allowing 2.3 HR/9, and Silva deserves a trophy for his 2.9 HR/9 rate — that’s 15 homeruns in 46 innings.

Homeruns are a function of allowing fly balls, so there might be hope for any of these pitchers if their batted-ball profiles are in line with previous seasons. In other words, perhaps hitters are just getting lucky this year. That might be true for Radke, as his fly ball rate is actually lower than at any point over the past five years. Lohse is allowing more fly balls than last year, but it’s not out of line with his previous three seasons. Silva, on the other hand, has suddenly become a fly ball pitcher, not a good idea for somebody who encourages hitters to get wood on the ball.

One last important aspect of pitching performance is actually a measure of the fielders behind the pitcher — allowing hits on balls in play. Considering that all three of our subjects allow a lot of balls in play, good fielding is critical for success. In 2006, the Twins have been the worst fielding team in the majors. Sure, they haven’t committed many errors, but that’s because, other than Torii Hunter, they don’t have the range to get to many balls.

Defensive Efficiency Ratio (DER) is the percentage of balls in play that get turned into outs. The Twins DER this season is .651 against a league average of about .700. The Tigers have the highest DER at .737. From a batter’s perspective, that’s the difference between hitting .267 and .349.

Compared to the rest of their careers, Carlos Silva, Brad Radke, and Kyle Lohse are all allowing more walks and more homeruns, they’re striking out fewer batters, and the Twins defense is letting a huge percentage of balls in play go for hits. It’s the perfect storm of pitching. I agree with the assessment that Silva needs a break from the rotation and while he probably won’t help the bullpen one bit, he needs to figure out how to ease his K/BB back towards his career level and reduce his fly ball rate.

Lohse may actually be the best of the three options right now, and could bring his ERA below 5.00 if he lowers his walk-rate. Radke’s ERA should fall as well, especially if his current homerun rate really is a fluke. But let’s not kid ourselves, the most positive news from this whole discussion is the fact that Francisco Liriano is now in the rotation. How long will it be before we see Boof Bonser (2.01 ERA in 49.1 IP) called up?