If Able, Sell High on Cain

San Francisco Giants righty Matt Cain is a hurler who many considered to be on the cusp of a major breakout. His performances during his first three years in the rotation were very good, to be sure, with Fielding Independent ERA’s ranging from 3.78 to 3.96 and strikeout-to-walk ratios hovering slightly over 2/1. Still, the sturdy 6-3 frame, low-90’s gas, hard slider, slow curve and changeup hinted that Cain could possibly reach another level.

If one were to take just a quick glance at Cain’s 2009 season, that breakout would appear to be in progress. After all, the 24 year-old’s notoriously poor run support that produced Maroth-like Win-Loss records hasn’t doomed him, as he sits at 4-1. His ERA checks in at a tidy 2.65 to boot. He’s an ace now, right?

Not so fast. Cain might possess the shiny W-L tally and a lower ERA than Lincecum, but in most respects, he has actually taken a step backward this season. Cain’s FIP is 4.85 in 51 frames, by far the highest mark of his career. His strikeout rate, which peaked at 8.45 batters per nine innings in 2006 and sat around the mid-sevens in ’07 and ’08, is just 6.00 in 2009.

The K rate wouldn’t be the end of the world if Cain had made commensurate improvement in terms of limiting the free passes. Unfortunately, he’s as wild as ever: 4.41 walks per nine innings. Batters seem to have taken note of Cain’s inability to locate, as opponents have offered at just 18.9% of pitches thrown outside of the strike zone (22.7% career average, 24.3% MLB average).

A true power pitcher when he broke into the big leagues (sitting between 93.2-93.4 MPH from 2005 to 2007), Cain now has a lower-octane fastball (91.6 MPH). In addition, his slider doesn’t appear to be the same knock-out pitch these days.

While it hasn’t surrendered any velocity, Cain’s slider isn’t moving away from righty batters like it used to. In 2007, the breaker tailed away from righties 3.8 inches more than a pitch thrown without spin. In 2008, that figure dipped to 3.4 (the league average for a righty pitcher) and comes in at just 2.6 inches this season.

The negative trend with Cain’s slider is also apparent through FanGraphs’ new pitch linear weights section (seriously, how cool is this stuff?): the slider was 1.37 runs above average per 100 pitches in ’07, 1.23 in ’08 and actually comes in at -2.33 runs per 100 pitches in 2009. Not coincidentally, Cain’s usage of the pitch has declined each year: 16.5% in 2007, 13.8% in 2008 and 10% this year. Those sliders have been replaced with more curveballs (from 8.6% in 2007 to 16.8% in 2009), which come in as below average (-0.76 runs per 100 pitches this season, -1.92 per 100 pitches in 2008).

Given these trends, it’s not especially surprising to see that Cain’s performance against same-side batters has trailed off (numbers courtesy of Baseball-Reference):

Cain vs. RHB:
2007: .224/.291/.370
2008: .235/.312/.378
2009: .293/.404/.500

None of this is to say that Cain is a bad pitcher, or that he won’t show improvement as the year goes on. However, his current levels aren’t anywhere near sustainable if he continues to post similar peripherals; he can’t continue to post a .257 BABIP or a near-90 percent strand rate. Cain is good, but he’s not the great pitcher that his surface stats would indicate. If you can cash in now by selling high, by all means do.