CHICAGO -- On Monday, Nationals manager Jim Riggleman talked about how the team needed to add an extra position player because three of its players -- Ryan Zimmerman, Willie Harris and Ivan Rodriguez -- are ailing.

With the benched strapped, the Nationals recalled outfielder Roger Bernadina from Triple-A Syracuse and optioned left-hander Jesse English to Syracuse following Tuesday's 3-1 victory over the Cubs. Bernadina is expected to arrive in time for Wednesday afternoon's game against Chicago.

Bernadina has hit safely in 12 of the 13 games he's played this season at the Triple-A level, including all seven games during the past week. Five of his past six games were multihit efforts, giving him a league-best 13 hits to go along with a .464 average for the week.

As for English, he posted a 3.86 ERA in seven appearances with Washington. General manager Mike Rizzo told the left-hander that he did nothing wrong. The club had seven relievers and the team needed an extra hitter. It also didn't help that English didn't see much action. He last pitched a week ago Tuesday against the Rockies.

"We told him, 'This is not a demotion. This is a strategic roster move, because we feel that we need to get a healthy position player in there,'" Rizzo said. "He didn't get as much work as we wanted to. We want him to go down there, pitch and get more work."

Zimmerman misses sixth straight start

CHICAGO -- Nationals third baseman Ryan Zimmerman didn't start his sixth consecutive game Tuesday because of a right hamstring injury that occurred last week against the Rockies.

Zimmerman said the injury is not serious enough to get an MRI, but the cold weather in Chicago is preventing him from loosening up his right leg properly. He is hoping that the warm weather in Florida will help him return to the lineup against the Marlins this weekend. Zimmerman has been making pinch-hitting appearances during the six-game layoff.

The big test for Zimmerman is running the bases, which he has yet to do. He has taken hitting and infield practice and ran in the outfield.

"I've done [almost] everything," Zimmerman said. "Obviously, it's harder to get loose [in Chicago]. I've done everything I'm planning on doing. I am coming along good, though. I didn't run the bases or anything, but I decided to run in the outfield. I felt OK. It's a little more each day. Obviously, we are being careful. It will be nice to get into warm weather."

Morse goes on rehab assignment

CHICAGO -- Nationals outfielder Mike Morse, on the disabled list because of a left calf injury, is going to Triple-A Syracuse to begin a rehab assignment, which will begin Wednesday. He could spend up to 20 days with Syracuse before the Nationals activate him to the big league club.

So he wouldn't get rusty with Syracuse, Morse spent the last week in extended spring camp in Viera, Fla., to get at-bats.

Burnett hasn't seen much action

CHICAGO -- Nationals left-hander Sean Burnett hasn't seen much action of late. Burnett pitched Monday against the Cubs, but that was his first game since last Tuesday against the Rockies.

Part of the problem has been that Washington's starting pitchers have gone deep in recent games, and the team wasn't in situations where it needed a lefty in the game. When it's time to use the bullpen, Matt Capps, Tyler Clippard and Brian Bruney usually get the call.

It's not like Burnett has been idle. He has been warming up in the bullpen during games. Burnett said he understood why he hasn't had much game action of late.

"I've gotten warmed up almost every day -- I think three or four times on Saturday," Burnett said. "It's a good thing that the starters are going deep in games, and it gives the relievers less opportunities. At the same time, it probably means you are in the ballgame and you are probably winning. That's a good thing for us."