Nats await tests on Stephen Strasburg

WASHINGTON -- As expected, the Washington Nationals put rookie pitcher Stephen Strasburg back on the 15-day disabled list Tuesday with a strained flexor tendon and there is concern in some corners of the organization that Strasburg has suffered a more serious elbow injury.

He is scheduled for another test this week on his strained right forearm.

Strasburg was on the disabled list earlier this month with tightness in his right shoulder. This is his first season in the majors after being the overall No. 1 pick in the 2009 draft.

The Nationals aren't sure when he will pitch again. He will undergo a magnetic resonance imaging arthrogram, where dye is injected into the arm to show contrast, on Thursday.

While pitching in Philadelphia last Saturday, Strasburg recoiled after throwing a pitch in the fifth inning, wincing, and after a Nationals trainer and manager Jim Riggleman visited the mound, Strasburg was removed from the game. After Strasburg had an MRI, the Nationals determined that he would need further testing.

The flexor tendon can impact the stability and the integrity of the elbow ligament. Some pitchers have missed months after tearing the flexor tendon. If Strasburg has torn the ligament in his right elbow, he likely would require reconstructive elbow surgery, most commonly known as Tommy John surgery, and would be sidelined a year.

The Nationals called up right-hander Collin Balester from Triple-A Syracuse. Riggleman said Balester would be used out of the bullpen.

Balester's stay could be a short one, however. The Nationals have not announced who will take Strasburg's scheduled start Thursday, and Balester could be sent back to the minors to make room for another pitcher.

Right-hander Jordan Zimmermann, sent to Syracuse on Aug. 1 after a minor league rehabilitation assignment following ligament replacement surgery performed in August 2009, could be recalled to make the start.

Riggleman said he had settled on a Thursday starter but would not announce his decision until the official roster move was made.

Senior baseball writer Buster Olney and information from The Associated Press contributed to this report.