(Al Behrman - AP) Nationals reliever Ryan Mattheus will visit a specialist in Baltimore on Tuesday to determine the severity of plantar fasciitis in his left foot. Depending on the diagnosis, Mattheus could either return in time to pitch Tuesday night or he could land on the disabled list and miss two weeks.

Mattheus has been pitching with soreness in his foot for about two weeks, he said, and he aggravated the injury Monday afternoon while jogging in the outfield. Mattheus underwent an X-ray Monday evening, which was negative.

Mattheus allowed two hits and a walk but no runs in one inning yesterday. For the season, Mattheus has a 2.25 ERA and 13 strikeouts with seven walks in 20 innings. With Henry Rodriguez no longer the Nationals’ clear-cut closer, Mattheus could be one of the candidates to get the ball in the ninth inning.

Second baseman-turned-utility man Steve Lombardozzi. (Greg Fiume - Getty Images) It came as a surprise to Steve Lombardozzi this afternoon when third base coach Bo Porter approached him and told him he would be starting in left field. He had played outfield once since April 9 and had not start there all season. Manager Davey Johnson had given no indication he would start playing more outfield.

“I didn’t know I was going to be out there,” Lombardozzi said. “But whatever they want me to do.”

Lombardozzi is also hitting leadoff tonight as Johnson tries to find more playing time for the second baseman-turned-utility man. In his part-time role, Lombardozzi has simply played too well not to garner more playing time. Among major leaguers with at least 80 plate appearances, Lombardozzi ranks 14th with a .407 on-base percentage.

(Jonathan Newton - WASHINGTON POST) The faithful at Citizens Bank Park offered boos for the mere mention of Bryce Harper’s name during pregame introductions. Harper backtracked a bit from his statement yesterday that he hoped fans would not throw batteries at him, saying Philadelphia has great fans who support all its teams. As for the incident in the team’s last meeting, when Cole Hamels admitted to drilling him with a pitch on purpose, Harper said, “I’m not even thinking about it.”

As always, talk about the game right here. And follow the action here.

(Patrick McDermott - GETTY IMAGES) Nationals reliever Ryan Mattheus received an X-ray today after he aggravated a left foot injury running in the outfield. Mattheus, Manager Davey Johnson said, had felt soreness in his foot for about two weeks. Mattheus will see a foot specialist tomorrow.

“Hopefully, he’ll be available tomorrow night,” Johnson said.

The Nationals’ bullpen is already without closer Drew Storen and backup closer Brad Lidge. If Mattheus’s injury is serious enough to knock him out of action, the Nationals could simply activate Chien-Ming Wang from the disabled list. The Nationals will use Wang in relief as he returns from a strained right hamstring, and he is scheduled to join the Nationals in Philadelphia tomorrow to throw a side session.

(Manuel Balce Ceneta - AP) After getting pulled from his start Sunday with fatigue and soreness in his right arm, Nationals ace Stephen Strasburg will make his next start as scheduled, Manager Davey Johnson said. The Nationals did not administer an MRI or any other significant tests, and they will monitor Strasburg this week as he performs his typical routine.

Both Johnson and pitching coach Steve McCatty said the Nationals do not regard the soreness as a significant issue. Rather, the Nationals believe the arm fatigue to be typical of any pitcher at this point in the season, particularly a starter, like Strasburg, who is not far removed from Tommy John surgery.

“I wasn’t really concerned that much yesterday when he came out,” Johnson said. “It was just normal tightness. But anything at all with him, that’s it.”