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5/29/2013 12:33 A.M. ET

Espinosa could return Wednesday vs. O's

WASHINGTON -- Nationals second baseman Danny Espinosa completed his regular pregame workout Tuesday and said that his fractured right wrist feels all right. Manager Davey Johnson said that if the wrist doesn't swell overnight, Espinosa could play Wednesday against the Orioles.

Espinosa has missed the past four games but told Johnson during Monday's game that he could pinch-hit or pinch-run if needed.

"Is it going to be 100 percent? No. I think we all know it's not going to be 100 percent for the rest of the year, because there's no casting or surgery they can do to make it 100 percent," Espinosa said. "It's just a time thing. But it does feel better. The biggest thing we were concerned about is the inflammation, and the inflammation's down."

Espinosa said the strength in his hand is fine but that he feels a constant clicking in his wrist when hitting. He has repeatedly said that his wrist does not feel 100 percent healthy, but that it has felt better over the past two days. He added that the torn rotator cuff in his left shoulder "feels great" and is not giving him any problems.

The 26-year-old played through the shoulder injury late last season and did not know about the bone chip in his wrist until more than five weeks after he was hit by a pitch against the Braves on April 14. On Tuesday, Espinosa said that he is struggling to gauge levels of pain.

"Am I supposed to feel much better than it does? How good am I supposed to feel?" he said. "I think everyone thought that I knew my shoulder was torn, and I had no idea. And then this is the same thing. I didn't know my wrist was broken and I'm tolerating. I thought it was a bone bruise."

Harper likely out through Thursday, at least

WASHINGTON -- After hinting Monday that Nationals outfielder Bryce Harper could be the designated hitter in the second half of Washington's home-and-home matchup against the Orioles this week, manager Davey Johnson said Tuesday that his 20-year-old slugger likely will miss the entire Interleague matchup with bursitis in his left knee.

"It's still tender, still a little bit swollen," Johnson said of Harper's knee. "The swelling's down a little bit. I was probably being a little optimistic thinking he could DH over in Baltimore. We're probably not looking good for that."

Harper was left out of the lineup again Tuesday after missing Monday's game. He injured his knee when he ran into the right-field wall at Dodger Stadium on May 13 and reinjured the same knee Sunday against the Phillies. He slid head-first into second and third base in the first inning, banging the knee on the ground.

While Harper will be out for a few more games, Johnson said this is not an injury that would land Harper on the disabled list.

"I think it's just when the inflammation gets out of there, the swelling gets out of there, he'll feel 100 percent better," Johnson said.

Werth headed to Potomac for rehab stint

WASHINGTON -- Nationals right fielder Jayson Werth, who is on the disabled list because of a right hamstring strain, will begin a rehab assignment at Class A Potomac on Wednesday.

Werth took 30 minutes of soft-toss batting practice and ran the bases on Tuesday before the Nationals' game against the Orioles. Both sessions took place before the team took regular batting practice.

"He looked outstanding, very strong," said hitting coach Rick Eckstein, who threw the pitches to Werth. "He was working on his positioning. We just had the better part of a half-hour of hitting. He did great. He looked wonderful."

Later in the afternoon, Werth was able to shag fly balls in center field and then take another round of batting practice with his teammates. There wasn't a report of a setback.

The Nationals are hoping that Werth can be back on a Major League field playing games sometime next week.

"He was moving around pretty good out there," Johnson said. "We just told him to take it easy and his reply was, 'I don't know how to take it easy.' But we'll see."

Nats reflect on Yocum's impact on baseball

WASHINGTON -- The Los Angeles Angels announced Tuesday that team doctor Lewis Yocum, one of the most respected surgeons in baseball, died this weekend of liver cancer. He was 65.

Yocum performed the Tommy John surgeries of Nationals pitchers Stephen Strasburg and Jordan Zimmermann and revealed second baseman Danny Espinosa's torn rotator cuff in the offseason. Yocum also helped set Espinosa's rehabilitation schedule.

Nationals manager Davey Johnson heard about Yocum's death Monday night.

"He's a legend," Johnson said. "I mean, doctors are such a big part [of the game] ... I don't think anybody in baseball has passed through without going to, being in front of Yocum or [Robert] Kerlan or [Frank] Jobe, [James] Andrews. They're just as much a part of the game as the players. They keep us on the field."

Zimmermann didn't know about Yocum's illness until this weekend. When he found out about it, Zimmermann sent Yocum a text message telling him to get well soon.

"I didn't know how bad it really was until 10 minutes ago," he said before batting practice Tuesday. "He saved a lot of guys' careers, he fixed a lot of guys and did a lot for the game of baseball.

"Obviously, he saved my career and I wouldn't be here without him."

Espinosa tore the rotator cuff in his left shoulder in September but wasn't initially aware of the tear. He sought a second opinion from Yocum after the season.

"It's tough to hear [about] his passing," said Espinosa, adding that Yocum also performed elbow surgery on his brother, Brandon. "He helped me out, he got me right, got me to his best physical therapist, and they got me in a position where he could get me going. It's definitely sad and it's a big loss for the baseball world."

Worth noting

• Johnson addressed the state of his bullpen Tuesday, saying that the recent performances of Fernando Abad, Henry Rodriguez and Drew Storen are all steps in the right direction.

"Abad's done the job a couple times out, and Henry's gotten much more consistent, he's throwing the ball good and throwing it over," Johnson said. "My concern really has been Storen. But Storen pitching like he's capable of, if he does that, that solves a lot of my problems."

• Rizzo said Tuesday that right-hander Christian Garcia (right forearm) is on track in his rehabilitation process. Garcia has been on the disabled list since March 22.

• Nationals utility man Jeff Kobernus had his first Major League at-bat in Tuesday's 9-3 win over the Orioles. He pinch-hit for pitcher Zach Duke in the sixth inning and grounded out to third base.

Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the Time. He also could be found on Twitter @WashingNats. Tom Schad is an associate reporter for MLB.com. Follow him on Twitter @Tom_Schad. This story was not subject to the approval of Major League Baseball or its clubs.