Sean Burnett Patrick McDermott/Getty Images

Sean Burnett has been dealing with a “little” irritation in his throwing elbow, a likely cause for his recent slide, and will rest for a couple of days, Nationals Manager Davey Johnson said Monday.

The left-hander has been near-automatic for the Nationals late in games, but over the past two and a half weeks he has struggled.  Burnett has allowed at least one run in five of his past seven outings and looked vulnerable. His control hasn’t been as sharp as it was.

Johnson believes the elbow issue is why Burnett’s performance has slipped slightly. Even so, Burnett is second in the Nationals bullpen with a 2.49 ERA, which shows how dominant he has been this season. Burnett hasn’t received an MRI, Johnson said.

Burnett, who had Tommy John ligament-replacement surgery in 2004, dealt with some tightness in the same elbow in mid-July. Burnett wasn’t placed on the disabled list then. He received treatment and his performance didn’t suffer.

Burnett has been stellar this season despite an increased workload. He is on pace to set a career-high with 74 appearances but his innings total will be down. Burnett has appeared in 61 games and 50 2/3 innings. Johnson has acknowledged using Burnett often because he has been so effective but doesn’t feel he has been overworked.

Because rosters expanded on Saturday, there’s no need to put Burnett on the disabled list. Instead, Johnson will give the left-hander time to rest and won’t use him in a game. Losing Burnett for a few days won’t hurt as the Nationals face a four-game series against the Cubs, who are out of playoff contention, because they added left-handers John Lannan and Zach Duke to the bullpen and because relievers Tom Gorzelanny and Michael Gonzalez have pitched well this season. But losing Burnett for an extended period of time would hurt. 

The Nationals noticed that something was awry when Burnett, who normally wouldn’t open his mouth about pain, sought treatment following Sunday’s game. Burnett allowed two singles and a two-run home run in the seventh inning that tied the game.