WASHINGTON -- Hot-hitting Kyle Schwarber exited Friday¡¯s 10-5 loss to the Dodgers in the second inning with a right hamstring injury. He will undergo an MRI on Saturday morning to determine the extent.

After singling to center field, the Nats' left fielder rounded first base and pulled up with visible discomfort in his right leg. He left the game moments later.

? Box score

¡°When you see a guy grab his leg like that ¡­ you¡¯ve got to get him out of the game,¡± manager Dave Martinez said, adding, ¡°He wanted to stay in, and there was no way he could stay in.¡±

Schwarber has been the sparkplug of the Nationals¡¯ offense since being moved to the leadoff spot mid-June. Game after game, he surpassed numerous milestones that made him part of elite slugging history. Earlier Friday afternoon, Schwarber was named National League Player of the Month after slugging 16 homers (seven leadoff dingers) in June. During last month, he topped the NL in home runs, slugging percentage (.760), OPS (1.122) and RBIs (30).

¡°You get very concerned and you hope that he can come out of it and be OK,¡± Martinez said. ¡°I spoke to him and I told him, ¡®Hey, regardless of what the MRI reads, there¡¯s still a lot of baseball left.¡¯ I¡¯m really proud of what he¡¯s been doing and we¡¯ll get you healthy and we¡¯ll get you back out there as soon as possible.¡±

Schwarber¡¯s exit was the latest blow to a lineup that had been clicking to the tune of 14 wins in its last 17 games of June in spite of a long list of injuries. Entering Friday, the Nationals had nine players on the injured list.

¡°It¡¯s frustrating,¡± said starter Max Scherzer. ¡°I don¡¯t feel like we have an injury bug -- we have an injury rat running around the clubhouse. It feels like it¡¯s just biting everybody at this point in time.¡±

Gerardo Parra replaced Schwarber in left field, where the Nationals already were shorthanded. Backup left fielder Andrew Stevenson is on the 10-day IL with a right oblique strain. Stevenson is slated to begin playing rehab games for Triple-A Rochester on Sunday. The Nationals want him to get 10 to 12 at-bats before he is activated -- ¡°But it might not be a long stint,¡± Martinez noted.

Between offensive outbursts, long innings by their starters and a strong month by closer Brad Hand, the Nats still rose to over .500 in spite of being without pitchers Stephen Strasburg (neck strain), Erick Fedde (left oblique strain), Daniel Hudson (right elbow inflammation), Tanner Rainey (stress reaction, right tibia), Kyle Finnegan (left hamstring strain) and Will Harris (right hand inflammation) for all of or points in time throughout June.

But injuries have hit position players, too, this week. Shortstop Trea Turner has been day to day since jamming his left middle finger on Wednesday while sliding into third base to complete the cycle. He is dealing with swelling, but he was able to move his hand on Friday. Turner is slated to complete strength tests on Saturday to help determine his availability.

Veteran utility infielder Jordy Mercer would have been an option to start in place of Turner, but he was placed on the 10-day IL on Friday with a right quad strain that has him feeling only 75 to 80 percent healthy.

? Nationals' injuries and roster moves

¡°We¡¯ve got to stay positive,¡± Martinez said. ¡°It¡¯s a long season, I¡¯ve always said that. We¡¯ve been kind of down and out in the past, and we survived and we¡¯ll do it again. I¡¯ve got all the confidence in the world in the guys that we have here to step up and help us win games.

¡°We¡¯ll try to go 1-0 tomorrow with the guys that are available, and we¡¯ll go from there.¡±