© 2014 MLB Advanced Media, L.P. All rights reserved.

4/24/2014 7:18 P.M. ET

'Pen session goes well, Fister set for rehab start

Nats righty likely to throw four frames and/or 60 pitches for Potomac on Sunday

WASHINGTON -- Doug Fister appears ready to make his next rehab appearance this weekend, according to Nationals manager Matt Williams.

Williams, in his pregame news conference Thursday, said that Fister (lat strain) felt fine after a 40-pitch bullpen session earlier in the day. His next start is scheduled for Sunday, which the manager thinks will be with the Class A Potomac Nationals of the Carolina League.

"He felt good in the bullpen today, so he's good to go for his next one," Williams said.

Williams said Fister would probably go around four innings and/or 60 pitches on Sunday. Fister has yet to pitch with Washington in the regular season, and Williams said the Nationals want him to build up and get stronger.

In fact, the manager said once Fister can get through five innings and be around 75 pitches that they'll consider him ready for a Major League start. But the Nats just don't know exactly how close Fister is to that yet, and they will monitor him once more after the next rehab outing.

"He feels good, ready for his next one," Williams said. "We look at it. It depends on how he feels. [When Fister returns] is still unclear."

Williams downplays Gio's shoulder tightness

WASHINGTON -- Manager Matt Williams said the Nationals will have a better idea of where pitcher Gio Gonzalez is with his shoulder in a few more days, but that he's not all that worried.

Williams said Thursday that Gonzalez, who came out of Wednesday's win over the Angels in the sixth inning due to some tightness in his left shoulder, felt normal day-after soreness.

The left-hander is scheduled for treatment, and the team's going to get a better look after his bullpen session in a few days.

"I'm not that concerned," Williams said. "It's just tightness, and I think that happens to pitchers over the course of a season anyway. I'm not concerned about it. I don't think he is either."

Gonzalez didn't seem too worried in the clubhouse before Thursday's game.

"It feels fine," Gonzalez said. "[Wednesday night it was] a little windy, you tend to tighten up a little bit. So you've got to stay loose, stay warm."

Hairston takes BP, moves closer to return

WASHINGTON -- Scott Hairston, on the disabled list since April 6 due to a left oblique strain, took batting practice again on Thursday and is also drawing closer to returning.

Manager Matt Williams said Hairston has a tentative plan they're working on. The outfielder was scheduled to take batting practice in the cage Thursday and then do early BP work Friday.

After that, Williams said that Hairston should take regular BP on Saturday, along with regular outfield drills. If everything goes well, then the Nationals will start having Hairston working on game situations.

"He felt good today coming in," Williams said. "After Saturday, we'll see."

Hairston's played in just two games this season, and he is 1-for-2 with one run scored.

Worth noting

• The Nationals are making a habit of come-from-behind wins. After rallying to beat the Angels, 5-4, on Wednesday night, Washington has now won seven of its 12 games in comeback fashion.

• Strikeouts have been the key so far for the Nats' pitching staff. They've fanned 212, which is tops in the Major Leagues. They're averaging 9.70 strikeouts per nine innings -- also best in the Majors.

Jeff Seidel is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.