By Steve Slowinski, Special to the Times
Saturday, May 28, 2011
It's widely said that hitting a 95 mph fastball is one of the most difficult things to do in professional sports. But even tougher is evaluating the player throwing that fastball and correctly predicting how he will perform in the future.
Pitchers are fickle. They can oscillate from a great start to the roof collapsing, and their career arcs are impossible to predict. Some pitchers peak in their early 20s and flame out (Scott Kazmir), and others don't put things together until they are in their 30s (Randy Johnson).
Also, it has been estimated that even the most durable pitchers have a 30 percent chance of going on the disabled list during a season. And pitchers can have their earned-run average bounce seemingly at random from season to season (look at James Shields' ERA over the past four years).
For a general manager, this uncertainty can lead to many sleepless nights.
But forecasting pitchers' careers becomes easier when a simple concept is followed: look only at things a pitcher can control.
A pitcher can't control many things. Bad defenders and home-run-prone ballparks can destroy a pitcher's ERA, and good defenders and large ballparks can do the opposite. And once a ball is in play, a pitcher has minimal impact on whether it falls for a hit or becomes an out.
Typically, 29 to 30 percent of balls in play fall for hits, whether a pitcher is an ace or a mid-rotation starter. Some dominant pitchers can cause hitters to make weak contact more often than others, but even then the difference is slight. For example, Greg Maddux had 28 percent of balls in play against him fall for hits over his career, representing only seven fewer hits per season than the average starter.
So when forecasting a pitcher's future, it's more useful to look at results a pitcher can control: strikeouts, walks and home runs allowed. In particular, it can be useful to look at a player's Fielding Independent Pitching (FIP), a statistic presented on the same scale as ERA but calculated using a pitcher's strikeouts, walks and home runs allowed in order to better predict performance.
Let's look at the Rays' Wade Davis as an example. By traditional metrics, Davis has pitched well this year. He has four wins and a 3.71 ERA, lower than he posted last season. You may have heard that Davis has intentionally decreased his fastball velocity in order to gain more control, and based on early returns, this approach must be good, right?
Not so much. Decreasing his velocity has made it tougher for Davis to fool batters. His strikeout rate has dropped significantly, from 6.0 strikeouts per nine innings pitched to 4.3. As a flyball pitcher, he has still been giving up his fair share of home runs (eight), and his walk rate has gotten worse from last season, from around 3.3 per nine innings to 4.0. As a result, he currently has a 5.03 FIP, second-worst on the Rays to Andy Sonnanstine.
With these changes, Davis has essentially become a duplicate of Sonnanstine: a low-strikeout pitcher who succeeds only when his command is spot on. If he's off with his location, players will rope multiple hits and home runs off him. For a pitcher who once averaged around 8.0 strikeouts per nine innings in Triple A, is this the sort of career path the Rays want him taking?
There were some positive signs from Davis' start against the Tigers on Tuesday. Pitching coach Jim Hickey and manager Joe Maddon have encouraged Davis to be more aggressive on the mound, and Davis' fastball velocity was up slightly. Davis still reverted to his cautious, lower-velocity self at times, but overall the start was a step in the right direction. He allowed four runs, but he struck out four, walked two and generated more whiffs with his pitches than he had in many of his previous starts.
The Rays have a lot of faith in Davis; they signed him to a four-year contract extension two months ago. His strikeout numbers will likely come back up again over time, but in the meantime, Rays fans should keep their fingers crossed that he has good command when on the mound.
Steve Slowinski is the editor-in-chief of DRaysBay.com, a blog on the Tampa Bay Rays that specializes in analysis and statistics.