(Manuel Balce Ceneta/AP)

Tracy will be given Saturday off because of it and could resume playing on Sunday. The setback is minor and not unexpected. Tracy said earlier this week that he was ahead of schedule with his rehab from surgery anyway and that he still didn’t have full strength in the area. He felt it most when he made quick cuts while playing third base or while running, he said.

“It’s kind of anticipated that you can have a little problem in that area but it’s a little more than just discomfort, so hopefully a little treatment and a day of rest and he can go back and resume,” Johnson said.

Tracy, 32, was expected to rejoin the Nationals for the first game after the all-star break later next week. In three games at Potomac, Tracy is 0 for 9 with one run scored, one RBI, one walk and one strikeout. He said he felt comfortable at the plate but needed more time to feel better in the field. He played third base one game and as a designated hitter the other two.

Johnson considers Tracy his biggest loss to injury of the season because of his value off the bench as a pinch-hitter in critical late-game situations. The left-hander batter went 6 for 18 with nine RBI off the bench before landing on the disabled list on May 28.

“I’m five weeks today from surgery,” Tracy said Thursday. “We were looking at six to eight weeks before I was back in the big leagues. Some people even said that I might be out the rest of the season. I’m pushing it as hard as I can right now. It’s still really early.”

Outfielder Xavier Nady is scheduled to begin his minor league rehab assignment with Potomac on Saturday. He is expected to hit third as a designated hitter. In 40 games and 102 at-bats, Nady is hitting .157/.211/.275 with three home runs and 6 RBI. He had been troubled with tendinitis in his right wrist and landed on disabled list on June 25. Nady, 33, is the 11th Nationals major leaguer to rehab in Potomac this season.

Reliever Drew Storen is also expected to appear in Potomac’s game on Saturday in relief, his second minor league appearance. Storen, 24, started Thursday’s game and needed only eight pitches to complete his only inning.

Storen is scheduled to make four total appearances, pitching every other day, with his final one likely on July 11. But if he breezes through his inning each game, he may have to make back-to-back appearances, Johnson said. Johnson’s biggest concerns about Storen are that he won’t build up his endurance, be challenged and use all of his pitches.

“Hopefully I want him to throw more than eight pitches, get a good workout down there,” Johnson said. “If not, I told him and [pitching coach Steve McCatty], rather than see him go to the bullpen and start throwing, I want to see him in a game situation because it’s not going to be like here. It’s going to raise up another 20 percent here. So I want to make sure everything has a good foundation for when he comes back up.”