Top Prospects: Lucas Giolito, RHP, Nationals

WASHINGTON -- Lucas Giolito, the Nationals' top prospect, hasn't pitched since May 11. General manager Mike Rizzo insisted that nothing is wrong with the right-hander. He is on an innings limit and is resting his arm. However, he is working in between starts.

Nationals pitchers are usually on an innings limit after having Tommy John surgery. Giolito had the procedure done in 2012 and returned late last season.

"This is part of his developmental program," Rizzo said. "He is doing what pitchers do in between starts. He is on an innings limit, but we want him to get through an entire season -- to feel what it's like to pitch at the end of August.

Giolito is off to a good start for Class A Hagerstown, going 2-0 with a 2.51 ERA and 36 strikeouts in 32 1/3 innings.

Zim takes BP for first time since thumb injury

Ryan Zimmerman takes some swings on Wednesday.

WASHINGTON -- On Wednesday afternoon, Nationals third baseman Ryan Zimmerman fielded ground balls and took batting practice for the first time since fracturing his right thumb against the Braves on April 12.

Zimmerman spent the entire fielding session at first base. He started by taking ground balls and making throws to second base before practicing scoops.

After that, Zimmerman concluded his workout with batting practice. Nationals ambassador and former Major League right-hander Livan Hernandez pitched the session.

Zimmerman also threw from around 120 feet. Depending on how he feels on Thursday, Zimmerman said he plans on stretching out to 150 feet.

"It felt good," Zimmerman said. "I think you've got to do that for a couple days to get in shape, make sure that you can go out and take BP every day and do your work without getting tired or without doing something to your back or your oblique. And that's kind of the point of these last two days and the next couple days."

Zimmerman said he could feel a little pain in his thumb during batting practice, but nothing substantial enough to prevent him from completing a full workout and swinging the bat the way he wants.

The third baseman sprayed a number of home runs to all fields, including a blast at the end of the session that landed several rows into the red seats in left-center field. Zimmerman said he "really got after it" in the weight room for around four or five weeks while he was injured because it was all he could do.

"I'm probably stronger than I was before," Zimmerman said. "So I'm not too worried about the strength, it's just more about being able to repeat the swing and swing like I normally swing before it happened."

Zimmerman related his return from injury to arriving at Spring Training. In both instances, he went an extended period of time without fielding, throwing or swinging, and experiencing soreness is part of the process.

"The first two or three days you swing, it's going to be sore," Zimmerman said. "From there, it usually starts to taper down and ware off."

Manager Matt Williams said he thought Zimmerman's timing was a little off, but that's typical from someone who hasn't seen live pitching in several weeks. More importantly, Zimmerman went through the workout with little-to-no pain despite hitting a ball off the end of the bat when Hernandez threw a curveball.

Williams wouldn't rule out a Minor League rehab stint in the near future. But he said the crucial thing is making sure Zimmerman is 100 percent healthy for the remainder of the 2014 season.

"Can you imagine pushing too fast and having him go out on a rehab assignment and pulling muscle?" Williams said. "That's what we don't want. When we get him back, we want him back for the rest of the season. So we're not going to push him too hard in that regard."

Zimmerman has worn a thumb guard during his career, and he will continue to do so when he returns from injury. He said he wore the guard during batting practice on Wednesday and didn't experience any problems.

"It all depends how I feel in the next day or two," Zimmerman said. "And we'll go from there."

Prospect Purke to undergo Tommy John surgery

STL@WSH: Purke pitches two scoreless frames

WASHINGTON -- Left-hander Matt Purke, the Nationals' No. 6 prospect, will have Tommy John surgery performed Thursday morning, according to general manager Mike Rizzo. The procedure will be performed by Dr. James Andrews.

Having the Tommy John procedure is nothing new to the organization. Pitchers such as Jordan Zimmermann, Stephen Strasburg and Lucas Giolito have gone under the knife for elbow reconstruction. Zimmermann and Strasburg have been successful in the big league level since the surgery. Giolito hasn't pitched since May 11 and is currently on an innings limit with Class A Hagerstown.

"Yeah, it's disappointing," Rizzo said about Purke. "He is going to be a year-plus of getting back, but we have been through this before with good results, so we are hoping for the same."

Purke was off to a slow start for Double-A Harrisburg, going 1-6 with an 8.04 ERA in eight starts.

Purke, a third-round selection in the 2011 First-Year Player Draft, has been hit by injuries ever since he joined the organization. He dealt with shoulder problems for most of his professional career.

Worth noting

•  Left-hander Gio Gonzalez (shoulder inflammation) threw on flat ground for the fifth straight day on Wednesday. Williams said if Gonzalez feels good, he would be scheduled for a bullpen on Thursday.