DeRosa Still Dinged Up

Signed to a two-year, $12 million deal by the San Francisco Giants over the winter, Mark DeRosa was supposed to provide his new employers with a good bat and position versatility. Similarly, fantasy players looked the former Brave, Ranger, Cub, Indian and Cardinal to hit at a decent clip while qualifying at third base, the outfield and first base. He stood a good chance of re-gaining eligibility at the keystone spot as well.

Unfortunately, DeRosa’s surgically repaired left wrist continues to hamper him at the plate. Possibly headed to the DL with a nerve irritation producing numbness in his left hand, DeRosa fumed to MLB.com’s Chris Haft:

A brutally honest Mark DeRosa said Tuesday that the left wrist surgery he underwent last year was a “total failure” and will remain out of the Giants’ lineup for at least a couple of days to determine his next course of action.

“When’s the last time I crushed a ball? I feel like my bottom hand’s underwater. I don’t have much feeling in my bottom two fingers,” said DeRosa, a right-handed batter.

DeRosa last played Saturday, when he went 0-for-5 at New York and didn’t hit the ball out of the infield in three at-bats against Mets starter Johan Santana.

“It came to a full head in my second at-bat,” DeRosa recalled. “[Santana’s] throwing 88, 89 [mph] and I was sitting on a middle-in fastball. It was there on a tee. I went to move on it. When it came out of his hand, I [said], ‘This is a bare minimum double to left-center.’ The next thing I know, it’s a weak popup to second base.”

DeRosa, 35, served a DL stint last July due to the wrist problem and went under the knife in October of ’09 to repair a torn tendon sheath. It’s often said that wrist injuries sap power, and Beyond the Box Score’s Dan Turkenkopf found some support for that baseball axiom.

The agitated Giant split the ’09 season between Cleveland and St. Louis, suffering the wrist injury right after the deal that brought him to the Cards for relievers Chris Perez and Jess Todd. DeRosa hit for a good deal of pop with both clubs, finishing the season with a .183 Isolated Power. Given his age, even a healthy DeRosa figured to hit for less power in 2010: CHONE (projected .153 ISO), ZiPS (.161) and the FANS (.164) all called for fewer extra-base hits.

So far, DeRosa looks like he’s swinging 20,000 leagues under the sea. In 104 plate appearances, he has a .194/.279/.258 triple-slash, with a .244 wOBA. DeRosa’s ISO is .065.

While it could be a coincidence, DeRosa’s typically solid plate discipline has tailed off since he suffered that wrist injury:

(For reference, the MLB average for outside swing rate is in the 25-27% range since 2007; it was closer to 20% from 2002-2006. The average first pitch strike percentage has remained steady at 58-59%.)

The biggest increase in swings has been on four-seam fastballs. According to Pitch F/X data from Trip Somers’ Texas Leaguers site, DeRosa offered at 39.8 percent of four-seamers with Cleveland (45.2% MLB average). With the Cardinals, that swing percentage rose to 52.8, and has remained high at 51.9% with San Fran in 2010. Again, we can’t definitely prove cause and effect, but DeRosa’s run value per 100 pitches against fastballs was +0.88 with Cleveland, +0.23 with St. Louis and is -2.28 with San Francisco this season.

With DeRosa ailing, John Bowker (.266/.337/.435 rest-of-season ZiPS projection) could benefit by logging more starts in left field. Given DeRosa’s health issues, owners should abandon ship.