WASHINGTON -- As Nationals manager Dave Martinez and head athletic trainer Paul Lessard emerged from the dugout and walked toward the mound in the second inning of Thursday’s 7-6 win against the Mets, Nats starter Anibal Sanchez screamed into his glove. In that moment he let out some frustration of yet another short outing on the mound, this one the result of a left hamstring strain that will put him on the injured list.

Sanchez is scheduled to receive a MRI on Friday to determine the extent of his injury, but in the aftermath of Thursday’s game at Nationals Park, the club knew he would miss at least one start and planned to put him on the IL.

“It's not serious, but let's see what they say tomorrow,” Sanchez said. “I can say I'm probably going to miss another start, but I don't yet. I just want to wait for tomorrow.”

Sanchez has a history of hamstring injuries in the past and has spent time on the injured list the past two seasons with those injuries, including missing six weeks last season with the Braves with a strained right hamstring. He did not believe this injury was the same as a year ago, or nearly as severe.

Sanchez had not been feeling any discomfort in his hamstring until the second inning, when he tweaked it on a pickoff throw to first base after a J.D. Davis single. He attempted to pitch through it, but after an eight-pitch walk to Brandon Nimmo he realized he could not continue.

“I just got a little twist and after, it's really hard for me to hold my body straight to home plate,” Sanchez said. “I tried to keep it as soft as I can, just to not put too much pressure on my leg, but it's my landing leg. There's nothing I can do. If I've got a leg problem, I can't even throw the ball straight to home plate.”

When the Nationals put Sanchez on the injured list, they are going to need a replacement in the rotation considering they do not have an off-day until May 30, two weeks from Thursday. Erick Fedde, who came in relief for Sanchez, is the top candidate to fill in that spot even though the Nationals converted him into a reliever a little more than a week ago. Fedde had not surrendered a run in his first four appearances from the bullpen before New York tagged him for four runs in the third inning.

Martinez didn’t commit to who would replace Sanchez in the rotation, saying the team was planning to weigh its options in the coming days. But there are not many. Joe Ross has been a reliever for a month and will likely require more time to build up his stamina or perhaps Kyle McGowin or Austin Voth could earn a promotion from the Minors for a spot start.

“We are going to keep our options open,” Martinez said. “We haven’t decided yet, I mean Fedde has been pitching well. So we’ll give him a couple days and see where he is at.”

The early exit and injury was especially frustrating for Sanchez, who was trying to turn around what has been a rough start to his first season in Washington. He retired the first four batters -- two via strikeout -- he faced and was hopeful to be on his way toward lowering his 5.10 ERA.

“That was probably as frustrated as he's gonna get,” said catcher Kurt Suzuki, who was also Sanchez’s teammate in Atlanta. “Just because he was really looking forward to getting back on track and for something like this to happen, it's pretty frustrating for him with everything that's kind of going on. But he'll be back, he'll be working hard and he'll be helping us here shortly.”