Manager Matt Williams is impressed by how the ball comes out of Blake Treinen's hand during bullpen sessions, and the skipper believes the right-hander has the ability to command the strike zone.

Treinen, who was rated by MLB.com as the 17th best prospect in the Nationals' farm system in 2013, can throw a sinker as fast as 95 mph. He also developed a changeup late last season.

Treinen, who came from Oakland in the Michael Morse trade, is a non-roster invitee and is expected to start the season for Triple-A Syracuse. Last season, Treinen played for Class A Auburn and Double-A Harrisburg, and he posted a combined 6-7 record with a 3.47 ERA. He will likely start the season as a starter, but the Nationals haven't ruled out a bullpen role for him.

"We are really excited to have him," assistant general manager Doug Harris said. "He is very big physically, very athletic young man, very good aptitude. He is a power sinkerballer. It varies from day to day. It's still evolving."

Treinen is willing to be a starter or a reliever for the Nationals.