Shrugging off a tight shoulder isn’t possible for Major League Baseball pitchers, who rely on their throwing arms to be in top shape in order to do their jobs. Such is the case of Colorado Rockies closer Huston Street, who has experienced some tightness in his throwing shoulder and will reportedly start the 2010 season on the disabled list (via Street dealt with what he called “minor” shoulder tightness earlier in spring training but thought he’d be fine.

A key pitcher, Street also missed a few weeks in September of last year with a biceps injury in his throwing arm. The team will now have to find a different part-time closer, despite signing Street to a three-year, $22.5 million deal over the winter. Manager Jim Tracy says Franklin Morales might fill in—as he did a few times last year—or Manny Corpas, the lights-out closer from the magical World Series run of 2007. The problem with both of those guys is inconsistency.

Morales can be dominating when he’s on point, but once he gets rattled, the wheels come off and things spiral quickly out of control. Last year, Corpas was mediocre at best, and he also missed significant time due to injuries in his throwing arm.

Meanwhile, pitcher Jorge De La Rosa has been impressive all spring and was the first Rockies pitcher to go five innings yesterday, as he led the Rockies to a 6-3 win over the Cleveland Indians, writes The Denver Post. De La Rosa has looked every bit the pitcher who led the Rockies in wins (16) last year, notes

There’s also good news behind the plate, with both catchers playing well. Chris Ianetta was set to start this year after the departure of Yorvit Torrealba, and Miguel Olivo was picked to be the backup. But The Denver Post reports both have been playing well enough to earn game time.