Will Yoder: Zimmerman likely to return today; what effect will he have?

Third baseman Ryan Zimmerman is scheduled to make his return to the Nationals lineup today after missing 58 games as a result of an abdominal injury. It's been a day the club has been looking forward to practically all season, and it's one that could desperately help the club out of its horrendous offensive slump. In his absence, the Nationals have gone 27-31 overall, but have survived on their stellar pitching. At the plate, the club has hit just .229, and has managed to score only 496 runs. Those numbers qualify them for the third lowest wOBA (weighted on-base average) and the worst batting average in the National League. Zimmerman's presence will provide an immediate impact simply on reputation alone. Currently, the batters in the middle of the Nationals order, most notably Jason Werth, are not seeing any pitches to hit because they are perceived as the club's only threats. With a bat like Zimmerman returning, opposing pitchers will have to start pitching to Werth in order to be able to afford to pitch around Zimmerman. This should help everyone through the lineup, one through nine. The real question is though, how effective can Zimmerman be immediately after his injury? A torn abdominal muscle can be a very difficult injury to come back from, even after surgery. Zimmerman will need time to get his timing back, adjust to major league pitching and learn how to hit every day once again. Even then, it's likely that he wont have the same power-hitting ability for at least a few months following his return. The ability to hit for contact comes from hand-eye coordination and quick wrists, but sluggers hit the ball out of the park by with torque and power generated from their core, which means that abdominal surgery is a major threat to middle-of-the-order batters. In June 2009, Texas Ranger Josh Hamilton underwent a similar surgery. His recovery time was actually rather short, as he was able to return to the field by July missing just over one month of service time. He suffered miserably the first month of his return, however, hitting .205/.244/.269. That was good for just a .513 OPS for one of the best hitters in baseball. The next month, he was able to find his stroke, hitting .342 in 29 games for Texas, but his power was still nowhere to be found as he hit just one home run and slugged just .447 in August (far below his .543 career mark). Hamilton, though, bounced back in 2010 as he led the league in batting and won the Most Valuable Player award, while still mashing a respectable 32 home runs for the pennant-winning Rangers. Unfortunately, not all players have faired so well after undergoing abdominal surgery. Chicago Cubs first baseman Carlos Pena underwent surgery for an abdominal tear in the winter of 2009, and hasn't been quite the same since. The season prior to the surgery, the 31-year-old led the American League with 39 home runs while posting a .839 OPS for Tampa Bay. The next season, in 144 games, the slugger hit 11 less home runs and saw his slugging percentage drop from .537 to .407. For Pena, now with the Chicago Cubs, 2011 has not been much better; through 61 games, he has hit only 13 extra-base hits, and is batting .216/.353/.373. The good news for Zimmerman is that, unlike Pena, he is a line drive hitter. That means that his outcome is likely to be more like that of Josh Hamilton, where he will see an immediate power dip but once he regains his timing will see his batting average remain about the same. In Pena's case, he is probably still trying to launch balls up and over the fence, and is finding that they are falling short with out the same strength he once had. Will Yoder blogs about the Nationals for The Nats Blog, and offers his viewpoints this week as part of MASNsports.com's season-long initiative of welcoming guest bloggers to our little corner of cyberspace. All opinions expressed are those of the guest bloggers, who are not employed by MASNsports.com but are just as passionate about their baseball as our roster of writers.