In 2011, Joe Saunders tossed 212 innings, posted a 3.69 ERA and won 12 games. Judging by those metrics, the Diamondbacks' decision to non-tender the 30-year-old seems curious. After all, why cut loose a workhorse lefty with an ERA much better than the NL average for starters (3.94)? The are two perfectly good reasons: Saunders has little chance of repeating that performance, and he's precisely the sort of pitcher who gets more money than he's worth in arbitration.
Saunders' 3.69 ERA was more the product of favorable bounces and timely outs than skill. Baseball Reference informs us that Saunders' nickname is "Bazooka Joe," but I'm not sure why. He struck out just 12.4% of the batters he faced, which ranked in the 15th percentile among starting pitchers (meaning he was worse than 85% of SP in that category). Saunders' control was OK but hardly Maddux-esque, as his 7.7 BB% placed in the 44th percentile. And he was worse than 82 percent of starters when it came to keeping the ball in the park, allowing a home run in 3.7% of opponent at-bats.
So, Saunders didn't miss bats, was a bit below average in avoiding walks and allowed lots of homers. How, then, did he post a 3.69 ERA when his Fielding Independent ERA was over a run higher, at 4.78? Saunders benefited from a .275 batting average on balls in play, which was 16 points lower than his mark from 2008-2010. He was especially lucky with runners in scoring position, with a .218 BABIP that was 80 points below his 2008-2010 average. In related news, Saunders stranded 77.7% of runners that got on base, compared to 72.1% the previous three years. That kind of Houdini act won't hold up.
Despite Saunders' dubious defense-independent stats, he was in for a handsome payday in arbitration. Research by Matt Swartz shows that arbitration panels mostly judge pitchers by back-of-the-baseball-card numbers: innings pitched, wins and ERA. And Saunders, with back-to-back 200+ inning seasons and 16-and-17 win campaigns in his past, was primed for a 2012 salary in the $8.5 to $9 million range. Considering that Saunders' 2012 ERA may well be closer to five than four (The Hardball Times' Oliver projects a 4.73 mark), that's a lot of coin for mediocrity. Plus, the Diamondbacks have arms like Josh Collmenter, Wade Miley and Barry Enright to fill out the back of their rotation. Top prospects like Trevor Bauer and Tyler Skaggs could debut later in the season, too.
Arizona's decision to non-tender Saunders makes sense whether the team tries to bring him back or not. He's not worth a $9 million salary next season, and other teams know that as well. As such, Saunders might get a multi-year offer but almost assuredly won't get $9 million per year. Players almost always get less money through arbitration than when they can market their services to all 30 clubs as a free agent, but Saunders' ERA and win totals mean more to arbitration panels than to teams who will note the discrepancy between results and process. After all, would you give $9 million to a durable Zach Duke?