Williams on De Los Santos, who replaced Treinen in 'pen: "Everybody loves his stuff"

The Nationals called up right-hander Abel De Los Santos on Monday and optioned right-hander Blake Treinen to Triple-A Syracuse.

The 22-year-old de Los Santos was 4-4 with a 2.65 ERA in 26 appearances for Double-A Harrisburg. He has not surrendered a run since June 8, a span of 15 innings over nine outings.

De Los Santos was acquired from the Texas Rangers, with second baseman Chris Bostick, in exchange for left-handed pitcher Ross Detwiler on Dec. 12, 2014.

"We don't know a lot because he's new to the organization this year," said Nationals manager Matt Williams. "We didn't get a chance to see him in spring training. But we certainly have reports from everybody that has seen him within the system. He's been closing some games for them pitching high leverage situations and back of the bullpen situations for them.

"Everybody loves his stuff. He's got good stuff, throws strikes. Got a breaking ball to go a long with it that he can spot when he needs to do, so he's been doing well."

Bostick has already moved up to Double-A. Former Nationals lefty Detwiler is now in the Braves bullpen after being released by the Rangers.

Treinen struggled in the ninth inning Sunday. He allowed four runs on five hits to the Dodgers, taking a 1-0 Nats' deficit and making it a 5-0 Dodgers' advantage. It was only his second appearance since July 6. Williams said this break from the team will give Treinen a chance to hone in on his approach.

"For Blake it's about consistency," Williams said. "We know the kind of talent he's got. It's heavy sink coming out of his hand at 97 or 98 mph. The issues that he has had with left-handed hitters this year is something to work on. Yesterday was an example of where he got ahead but he just couldn't finish.

"We'll give him an opportunity to get down there and get that consistent work and get him stretched out if we can. He'll be able to go down and throw three innings if we needed him to do that. He's perfectly fine to do that. He'll just work on some things and be back here quickly."

Did Treinen falter because he has pitched only three full innings since June 28, just not getting enough repetition?

"It's a function of where you're at as a team and how deep your starters are going," Williams said. "If we've got the matchups in the eighth inning and of course Drew (Storen) in the ninth, or Casey (Janssen's) doing a great job in the eighth and we're set there, and we get our starters through seven, then the opportunities just aren't there.

"That being said he's got tremendous stuff. He'll go down and work hard and refine and be back quickly as far as I'm concerned."