Reliever Henry Rodriguez has not pitched in a game since Thursday and will not appear in another game until he feels comfortable with mechanics he believes are currently “out of whack,” Manager Jim Riggleman said. In the meantime, Rodriguez has only thrown bullpen sessions with pitching coach Steve McCatty, trying to improve his shaky control.

This spring, which Rodriguez began late after a visa issue kept him in Venezuela, Rodriguez has walked three batters and yielded two earned runs in just 2 1/3 innings. Rodriguez retired all three hitters he faced in his last outing, but he threw one pitch behind a batter’s head that would have been ball four had it not inadvertently struck the bat and another pitch at a hitter’s feet.

The Nationals believe Rodriguez is healthy. “I don’t think there’s any issues there,” Riggleman said. “He’s concerned more about his delivery. He feels he’s out of sync. [McCatty is] going to try to schedule him in there when we can and see if we can get him throwing more strikes.”

The Nationals acquired Rodriguez this winter in the trade that sent left fielder Josh Willingham to the Oakland A’s. He came equipped with 100-mph fastballs and a history of control issues. Rodriguez has walked or hit 17 of the 141 major league batters he’s faced in parts of 2009 and 2010.

Rodriguez’s latest issues pose a significant problem for the Nationals’ as they make their final roster decisions. Riggleman said Rodriguez could not hold a place on the roster unless he pitches again this spring and finds at least some semblance of control.

But Rodriguez is out of options, and simply losing him seems like an untenable prospect considering they gave up their left fielder to get Rodriguez and minor league outfielder Corey Brown. The Nationals already have to somehow wedge eight relieves (Rodriguez, Chad Gaudin, Brian Broderick, Drew Storen, Sean Burnett, Tyler Clippard, Todd Coffey and Doug Slaten) into seven spots. That’s not even counting Collin Balester, who showed a wicked curveball today as he pitched a 1-2-3 inning with two strikeouts to lower his spring ERA to 1.93.

If Rodriguez cannot figure out his control issues, he may end up simply clogging things up and providing a lesson: There is value merely in a roster spot.