WASHINGTON -- This past Saturday, the Nationals had a chance to acquire then-Astros center fielder Michael Bourn, but Houston wanted left-hander Ross Detwiler to be part of any deal the two clubs make and Washington declined, according to a baseball source.

Bourn was dealt to the Braves the next morning. The Nationals have been in a need of a center fielder since the season started. They tried to acquire Twins outfielder Denard Span, but couldn't get him before the non-waiver Trade Deadline.

Right now, Rick Ankiel is the everyday center fielder for Washington. Entering Tuesday's game against the Braves, he is 20-for-59 (.359) with four home runs and 10 RBIs since coming of the disabled list on July 1.

Simulated game preps Strasburg for rehab stint

WASHINGTON -- Nationals right-hander Stephen Strasburg had a simulated game on Tuesday in Viera, Fla., according to Florida Today. He threw 51 pitches, with 32 for strikes.

While nothing has been made official, Strasburg more than likely will pitch in his first rehab game in the next "six to nine days," according to manager Davey Johnson.

Strasburg most likely will start his assignment with Class A Hagerstown. Strasburg and the Nationals are hoping that he will pitch in the big leagues sometime in September.

"I've heard tentative dates," Johnson said regarding the rehab assignment. "Those dates could vary. The weather could vary. ... If everything goes according to schedule, like I told you before, he might go somewhere and start a game, get two or three innings around [Aug.] 7th or the 10th. That is what I heard."

Strasburg, who is recovering from Tommy John surgery, has not pitched in a big league game this year.

Strasburg is considered the future ace of Washington's pitching staff. In his short stint with the Nationals last year, the No. 1 overall pick in the 2009 First-Year Player Draft was 5-3 with a 2.91 ERA in 12 starts. He struck out 92 in 68 innings.

Nats' Espinosa impressing his skipper

WASHINGTON -- Nationals second baseman Danny Espinosa was in a 4-for-51 slump entering Tuesday's action against the Braves. Manager Davey Johnson has been thinking about giving Espinosa a day off, but he is not in favor of taking a break.

Johnson acknowledged that he doesn't want to give Espinosa a day off, either.

"I enjoy watching him play," Johnson said. "He has hit the ball on the nose a bunch of times and he has come up empty."

Espinosa is a National League Rookie of the Year candidate, as well as Braves first baseman Freddie Freeman and closer Craig Kimbrel. Johnson believes that Espinosa is the best of the three.

"I like my guy," Johnson said. "He is a middle of the diamond guy, he produces runs, hits home runs, outstanding defensively. If he doesn't win it, he will be right at the top."

Balester pleased to be back up in bigs

WASHINGTON -- A day after they optioned left-hander Atahualpa Severino to Triple-A Syracuse, the Nationals recalled right-hander Collin Balester from Syracuse on Tuesday. It is Balester's third stint with the Nationals this season.

Entering Tuesday's action, Balester had a 4.61 ERA in eight appearances with Washington in 2011. Balester is expected to be the long man out of the bullpen.

"It's always great to be back. This is where you want to be," Balester said. "You want to be on this team, competing at this level. The last couple of years, I've been up and down so many times, but it's great to be back."

Swinging the bat still giving Pudge pain

WASHINGTON -- Nationals catcher Ivan Rodriguez is still feeling some tightness in his right oblique, according to manager Davey Johnson. Rodriguez, who has spent more than a week in Miami to fix his problem, is expected to be in Washington on Wednesday.

Johnson said Rodriguez will test the oblique by playing in Minor League games soon.

Rodriguez, who has been on the disabled list since July 7, doesn't have any problems catching behind the plate or throwing the baseball, but he can still feel the pain when he is swinging a bat.