By The Numbers: Sacramento Pitching Staff

The Sacramento River Cats pitching staff currently ranks fifth in the Pacific Coast League in ERA. Nathaniel Stoltz takes a closer look at the individual pitchers on the River Cats' staff to see whose ERAs are an accurate assessment of their performance thus far this season, and whose are misleading.

All stats good through Wednesday, May 27

This is the first article in a four-part series that will examine the pitchers at each level of the Oakland A's system and their true levels of performance. Often ERA and even WHIP can be distorted by luck, good or bad, so it's important to keep that in mind. Without further ado, here is how all the Sacramento pitchers have performed this year:

Top prospect Vince Mazzaro may not deserve his 2.38 ERA, but he's pitched extremely well this year and looks ready for the majors right now. His ERA should be about a run higher, but he gets a lot of ground balls (59%) while keeping a good strikeout-to-walk ratio (2.59 K/BB). A BABIP in the .250 range slightly inflates Mazzaro's value, but he may be a better option than Trevor Cahill at this point.

James Simmons has an odd statline. His K/BB ratio (1.47) is nothing special, but his low homer rate (.61 HR/9) and .352 BABIP indicate that he's done much better than his 5.32 ERA would indicate. Deeper down, however, there is evidence to the contrary. Simmons has an extremely low groundball rate (26%) and gives up an incredible number of outfield flies (50%). Because of this extreme split, the low homer rate looks like a fluke, as his flyball-to-homer rate (4.3%) is flukishly low. However, extreme flyball pitchers have lower BABIPs, so Simmons' bad luck there should correct even more than average as the season continues, into the .280 range instead of the normal .300-.310. It's unclear where all the looming corrections will pull Simmons' overall performance, but it's reasonable to think of him as a pitcher with an ERA around 4.50.

Gio Gonzalez needs to cut down on his walks. He's walking 6.16 batters per 9 innings this year, a rate that's at least 2 BB/9 too high. It says a lot about Gonzalez's strengths, however, that he has a pretty legitimate 4.70 ERA with all the command problems. His high homer rate (1.57/9 IP) is a fluke; expect that to come down to the 1.1-1.3 range as the season progresses. I've long had a theory about Gonzalez that he needs some time to adapt to each new level, and I still think he has front-of-the-rotation potential in 2011 or 2012. Be patient with him.

Ryan Webb's Triple-A debut has gone much better than his 5.22 ERA would indicate. The high ERA is the product of a .387 BABIP. Webb seems to be finally putting his mid-90's sinker to good use, getting a decent percentage of grounders (48.9%) while throwing enough strikes to get by (3.99 BB/9, 1.85 K/BB). Webb's ERA should be about a run lower than it is. He's not MLB-ready yet, but he's getting close.

Chad Reineke has been just about average in every category (walks, strikeouts, homers, GB%, BABIP, HR/FB%), meaning that his 5.02 ERA is actually exactly what he should have. He needs to show above-average ability in something to be more than an emergency option for the A's.

Jay Marshall doesn't deserve his 1.54 ERA, but like Mazzaro, he's certainly been good enough to earn a shot with the A's. Marshall has exhibited great control (1.21 BB/9) and groundball tendencies (54.5 GB%), meaning that in order to beat him, hitters just have to hope to sneak grounders through the infield. Marshall depends heavily on his defense, as he doesn't get many K's (4.74 K/9), but he deserves an ERA around 3.00 and is ready to wear an A's uniform for the first time since 2007.

Dana Eveland actually didn't pitch that badly in Oakland, deserving an ERA around 5.00, but he hasn't pitched well with Sacramento, meriting an ERA closer to 6.00. Eveland's BABIP, an extreme .421 with the A's, is .293 in Sacramento, a little lower than one would usually see from a groundball pitcher. Eveland needs to improve his K/BB ratio (0.91 with the River Cats, 0.94 with the A's) if he's going to succeed at any level.

Another pitcher who probably deserves to be in Oakland is Chris Schroder. His .190 BABIP gives him a 2.25 ERA he doesn't deserve, but the 3.50ish mark he does deserve is still excellent. Schroder's HR/FB rate is too low (3.8%) as well, but with a career MLB ERA of 4.46 and strikeout rate of 9.72 K/9, he can help out a bullpen. Schroder's problem is that he's a medium-sized righty with a 90-95 mph fastball and strong slider, and the A's already have two of those (Santiago Casilla and Michael Wuertz) in the major league bullpen, so Schroder is blocked.

Brad Kilby has been the best pitcher on the team, deserving an ERA just above 2.00. Of course, his .105 BABIP is a fluke, but like Marshall, he's ready for the majors now, adding to the list of reliable options the A's can turn to if any of the big league relievers struggle or get hurt.

Jerry Blevins doesn't deserve a 6.60 ERA, but the 5.87 mark he does deserve doesn't inspire confidence. Blevins' velocity is down about 3 mph on all of his pitches this year, suggesting that there could be something physically or mechanically to blame for the lefty's struggles. Until he finds a way to get his old stuff back, it's doubtful Blevins' stats will resemble what we're used to from him.

Sean Gallagher has nothing left to prove in the minors, as he has dominated PCL hitters in three starts, deserving a mid-2s ERA. His Oakland stint wasn't bad, either, as he deserved a mid-4s ERA. His .397 MLB BABIP distorts his stats considerably. In my opinion, Gallagher and Mazzaro would be better in the Oakland rotation right now than Trevor Cahill and Edgar Gonzalez.

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