Blake Treinen. (Mitchell Layton/Getty Images)

Blake Treinen will be called up from Class AAA Syracuse and will start Tuesday’s game against the Dodgers, Manager Matt Williams said after Monday’s 4-0 win. In order to make room on the roster, the Nationals will option reliever Ryan Mattheus to Syracuse.

At Syracuse, Treinen has been starting and has thrown only one inning in seven days. He started on April 28 and fired four innings and his most recent appearance was on May 3, a one-inning outing. Treinen had an April stint with the Nationals in a long reliever-type role and allowed only one run while striking out seven over 6 2/3 innings. For his first major league start, Treinen will be opposed by Clayton Kershaw, the Dodgers’ two-time National League Cy Young Award winner.

The Nationals were choosing between Ross Detwiler, a former starter in the bullpen, and Treinen. Detwiler was held out of games as insurance and hasn’t pitched in six days. He did warm up in the bullpen in the ninth inning of Monday’s game. The Nationals chose Treinen because he has been starting while Detwiler and Craig Stammen haven’t. The two also provide innings while Treinen can be a fresh arm for the one spot start.

“He’s been in that regular rotation,” Williams said. “We certainly wanted to stay away from Stammer and Det as much as possible in the last couple of days and we got an opportunity to do that so we have some length.”

>>> Nate McLouth has a sore knee, cut on his finger and bent his thumb back on a spectacular diving catch in foul territory in left field during the eighth inning of Monday’s game. McLouth dove, backhanded the ball about two feet away from the wall in left and slammed violently into it.

Williams and trainer Lee Kuntz came out to check on McLouth, who was replaced by Kevin Frandsen. A doctor evaluated McLouth after the game and, according to Williams, will be fine. (The animated gif of the play below is courtesy @federalbaseball.)

“He sold out,” Williams said. “On that play, he’s got to go for the ball and not pay any attention to where his body is going to be. That’s a great play.”