(Patrick McDermott/GETTY IMAGES)

“Hopefully, he’ll be available tomorrow night,” Johnson said.

The Nationals’ bullpen is already without closer Drew Storen and backup closer Brad Lidge. If Mattheus’s injury is serious enough to knock him out of action, the Nationals could simply activate Chien-Ming Wang from the disabled list. The Nationals will use Wang in relief as he returns from a strained right hamstring, and he is scheduled to join the Nationals in Philadelphia tomorrow to throw a side session.

Mattheus allowed two hits and a walk but no runs in one inning yesterday. For the season, Mattheus has a 2.25 ERA and 13 strikeouts with seven walks in 20 innings. Mattheus, Johnson said, would not have been available to pitch tonight, anyway.

Lidge, meanwhile, traveled with the Nationals to Philadelphia. He made progress in his throwing program today as he rehabs from hernia surgery. He threw roughly 200 feet, and he rifled hs final throws at about full strength.

Lidge will throw his first bullpen session since the surgery Wednesday in Philadelphia, and on Thursday he will report to Florida for extended spring training. Lidge still expects to return somewhere around June 15.

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