WASHINGTON -- Triple-A Syracuse right-hander Josh Wilkie has been suspended for 50 because of use of "a drug of abuse," according to a baseball source. General manager Mike Rizzo declined to comment on Wilkie's suspension.

Wilkie was having one of the worst years of his career out of the bullpen, going 0-2 with a 4.76 ERA for the Chiefs. Wilkie is best known for getting a tryout with the Nationals with the help from former outfielder Jose Guillen. Wilkie ended up signing a free-agent contract with the team in 2006.

Triple-A Syracuse infielder Josh Johnson was also placed on the restricted list. It's not known why he was placed on the list. A career Minor Leaguer, Johnson was hitting .233 with 10 RBIs for the Chiefs.

Tracy's absence leaves hole on Nats' bench

WASHINGTON -- Nationals infielder Chad Tracy, who is out six to eight weeks because of a right adductor strain, is hoping to return to big league action by late July or early August.

Tracy injured himself last Saturday against the Braves in Atlanta. With a runner on second and the game tied at 4, Tracy hit Kris Medlen's 1-0 pitch into the gap in left-center field for a double, scoring Ian Desmond. It was Tracy's Major League-leading ninth pinch-hit RBI of the season. But Tracy came up hobbling while running to second base.

"I never felt anything like that. I had a feeling it was pretty bad," Tracy said.

Tracy was having a great year off the bench, going 8-for-18 (.444) with a home run and the nine RBIs. Tracy said he was having a good year because he felt comfortable being a member of the Nationals.

"I was in a good place, I relaxed. I felt like I belonged here," Tracy said. "I felt comfortable with everybody in this clubhouse. I felt like the staff, and especially [general manager Mike] Rizzo, were behind me and they wanted me to succeed. It's a good place."

Johnson supports Espinosa switch-hitting

WASHINGTON -- Entering Saturday's action against the Braves, second baseman Danny Espinosa was hitting .333 from the right side of the plate and .190 from the left side.

Manager Davey Johnson said the organization has not thought about having Espinosa bat strictly from the right side. In fact, Johnson believes that Espinosa is getting his act together from the left side.

"He has great potential from the left side. I think a lot of it is his mental approach, and we have been talking about that," Johnson said. "I think he is in a good place right now. Sometimes, as a young hitter, a little mental approach can affect your performance, and I think he is a prime example."

Ramos has surgery; Nats patient with Mattheus

WASHINGTON -- Catcher Wilson Ramos had surgery on his right meniscus recently, but manager Davey Johnson said Ramos still needed to have surgery on his anterior cruciate ligament and will have it done at a later date. According to Johnson, the doctor wants the meniscus to heal before Ramos has another surgery.

Ramos suffered the knee injury on May 12 in the seventh inning against the Reds, as he chased after a ball that had ricocheted off his glove on a pitch from Jordan Zimmermann.

In other injury news, right-hander Ryan Mattheus said his left foot is feeling better and he is now throwing on flat ground. Mattheus is not sure when he will start a rehab assignment, but Johnson said the team is going be cautious when it comes to Mattheus, who is on the DL because of a plantar fascia strain.

"It's still tender. The concern is that if he were to field a ground ball or made a turn -- it's his landing foot, not his push-off foot -- he could tear [the plantar fascia] even further, and that would not be a good thing," Johnson said. "We are probably going to be cautious with him. If you talk to Ryan, he will say, 'I'm ready to pitch.' The doctors are being conservative on it, and rightfully so."

Infielder/outfielder Mark DeRosa, who is on the disabled list because of a left oblique strain, worked out on Saturday at Nationals Park without any problems and will more than likely start a rehab assignment with Class A Potomac, according to Johnson.

DeRosa most likely get four at-bats and then be a candidate to return to the team. The team needs help off the bench after Chad Tracy went down with a right adductor strain.

Reliever Brad Lidge is looking to start a rehab assignment early next week for Class A Potomac and hopes to rejoin the team during the Red Sox series starting June 8, or the following three-game series against the Blue Jays.