PHILADELPHIA -- The Phillies are accustomed to injuries by now. Their stars have so frequently populated the disabled list this season that they may not have felt much sympathy for Washington when its 21-year-old phenom, Stephen Strasburg, left Saturday's game wincing at his golden right arm.

Philadelphia was trying to celebrate the return from injury of its own renowned slugger, first baseman Ryan Howard. But even that quickly took a backseat to the sight of Strasburg walking off the mound in the fifth, flanked by trainers.

Washington went on to win, 8-1, in front of 45,266 at Citizens Bank Park, but Nats fans will no doubt be more interested in hearing the prognosis on the young face of a last-place franchise. The Nationals initially termed it a flexor tendon strain of the forearm, and he will get an MRI on Sunday.

"I didn't want to see him leave that way," Phillies manager Charlie Manuel said. "He's got good stuff. He really has got tremendous stuff."

Strasburg, the No. 1 overall pick in last year's First-Year Player Draft, was making his debut against the division-rival Phillies and looked good doing it. He had given up only two hits and one run with six strikeouts as he pitched with one out in the fifth.

But Strasburg's 56th pitch of the night left him with a twisted look on his face and a glance at his right arm. Washington's training staff immediately ran to the mound and the 21-year-old was removed after several minutes of discussion. He disappeared down the Nationals tunnel and wasn't available for comment after the game.

Howard's return after 16 games on the disabled list with a right ankle sprain gave the Phillies their full hitting arsenal for the first time in months. But they fell behind 3-0 in the first inning as Kyle Kendrick fumbled with his command, walking three, including Adam Kennedy with the bases loaded. Washington added two more runs in the third, including an RBI groundout by Strasburg.

"Besides the first inning, I thought I threw the ball well," Kendrick said. "But the command was horrible in that first inning -- falling behind, walking guys -- that's not me. I just needed to fix that first inning."

Kendrick was 3-1 with a 3.03 ERA in his past five starts coming into Saturday and appeared to be solidifying his slot as a dependable No. 5 starter. He settled down after a long first inning, but gave up five runs on nine hits in 5 2/3 innings.

"He was having trouble with left-handed hitters and throwing strikes," Manuel said. "They hit some balls hard."

Philadelphia's lineup never clicked even with the infusion of Howard, who leads the team with 23 home runs and 82 RBIs. It managed only four hits and didn't work a single walk. Howard went 1-for-4 with an RBI, but struck out with two runners on in the sixth.

"It was good," Howard said. "Went out there, ankle felt good. Unfortunately we came up short tonight."

Howard was activated off the disabled list earlier than expected, after playing one Minor League rehab game for Class A Lakewood on Friday. Manuel said he would check on how Howard feels Sunday to determine whether he needs a day off or not.

"The concern was more how it would feel the next day after the game," Howard said. "I woke up this morning, it was a little stiff, but that's to be expected. There's still a little swelling and stiffness in there, but once I kind of get it loosened up and warmed up its ready to go."

Strasburg was supposed to start on Aug. 1 against the Phillies, but was scratched due to elbow stiffness. He spent two weeks on the disabled list.

On Saturday, he started as sharp as promised. With a dizzying curveball -- which buckled hitters on more than one occasion -- and a hard changeup. Strasburg was finely cutting through Philadelphia's lineup. He ran into trouble only in the fourth, when a leadoff double by Placido Polanco led to a run on a groundout by Howard.

Strasburg had just recorded his sixth strikeout when his pitch to Domonic Brown resulted in the injury. The crowd hushed as a succession of trainers and coaches ran to the mound.

"You never want to see anybody get injured," Howard said. "I don't know exactly what it was -- it looked like he had some sort of discomfort in his arm after he threw the pitch. I hope he has a speedy recovery."

Kendrick wished the phenom the best as well.

"Scary," Kendrick said. "I guess they said they heard his elbow pop. That's never good, hopefully everything turns out well."

With the ace right-hander out of the game, Philadelphia still couldn't capitalize. Howard hit a deep fly ball to left-center field that was robbed by a leaping Bernadina at the wall in the ninth -- one of the few hard-hit balls on the night by the Phillies, who didn't showcase their newly healed lineup as proudly as they would have liked.

"We got out of the gate bad," Manuel said. "We couldn't get anything going."