(Patrick Semansky/AP)

Earlier in the day, Burnett described the injury to be far less serious. He received treatment today and said his elbow felt much better afterward. He planned to play catch pregame as a small test and hoped he would be available to pitch in tonight’s game. Burnett chatted with reporters before he played catch, seemingly unworried.

Burnett had Tommy John ligament-replacement surgery early in his career, at age 21 in 2004. While he is optimstic the injury is not serious, his experience colors his current outlook.

“Hopefully, there is no story,” Burnett said. “Hopefully, it’ll go away. When you’ve had surgery before, you don’t like to even think about any of that kind of stuff.”

The Nationals, Johnson said, plan to have Burnett see team doctor Wiemi Douoguih for tests when they return to Washington on Tuesday. The lingering tightness has had no effect on his results, Burnett said. Even last night, Burnett “threw the heck out of the ball,” Johnson said. He struck out the batter he faced on five pitches.

“He’s too valuable to us to take a chance,” Johnson said. “The thing that concerns me is he’s had four days off at the break, and he’s having a little bit of problem in there. From what I gather, it’s been bothering him for some time. If it’s something that concerns him and he says he can pitch with it, it still scares the heck out of me.”

If Burnett misses time, the Nationals will be left with Michael Gonzalez and Tom Gorzelanny, who is typically used as a long man, as their only two left-handed relievers. But it would be difficult replace Burnett, who has pitched this year like a borderline all-star.

Burnett said the lingering tightness had no bearing on his results, and it showed. He has allowed seven earned runs in 32 innings, striking out 33 while walking seven. He has served as Tyler Clippard’s primary set-up man for the past month.

With Burnett possibly set to miss time, the Nationals are also about to get Drew Storen back from the disabled list. Storen, who saved 43 games last year, has not pitched all season while recovering from surgery in mid-April to remove a bone chip from his right elbow. He is close to a return, having made four minor league rehab appearances, with a fifth set for tomorrow at Class AA Harrisburg.

It seems convenient for Storen to be returning now, with Burnett’s potential absence surfacing. But Johnson said he would not factor Storen’s return into Burnett’s health situation.

“That’s just not something we can arbitrarily do,” Johnson said. “What we want to do is what’s best for him.”