(Paul Sancya/AP)

Wang, who pitched a rehab start Saturday, will warm up during tonight’s game in order for Davey Johnson to get a feel for how long he takes to warm up. Wang has made only five relief appearances in his career and has been pitched out of the bullpen for an extended period.

“He likes to throw long [toss] and I don’t know how many pitches he needs to get really feeling good,” Johnson said. “Today I’ll probably warm him up during the game and count his pitches, monitor his time. He’s too valuable to this organization and his future’s too valuable that I’m not going to use him as a normal reliever. I’m going to give him plenty of time while he’s out there before he comes in the ballgame.”

After today, Wang will probably not be available to pitch until Friday. The Nationals will be shorthanded in the bullpen without Mattheus, who could have become a candidate to close games with Henry Rodriguez moved to a less demanding role. Instead, Mattheus became the 11th National on the disabled list this year. He will wear a boot for two weeks and could, Johnson said, miss up to a month.

“That’s a big blow,” Johnson said. “And at the same time, having Henry have another hiccup, that didn’t help either. We’ve been kind of devastated. It’s been kind of making us regroup, revamp. But it’s not like something we’re not used to.”

Despite an extended warm-up routine made necessary by the shoulder surgery he recovered from for all of 2010, Wang expressed no qualms with pitching out of the bullpen.

“I’m just glad the team still gives me this opportunity,” Wang said. “I’m going to try my best to get the job done and try to help the team win the game.”

More from The Washington Post:

Nationals move Rodriguez out of closer’s role

Tuesday’s lineups

Wang activated, Mattheus to DL

Phillies:Harper got extra security

Desmond’s home run binge

Nationals defeat Phillies, 2-1

Gonzalez among the elite

Mattheus to visit specialist