BOSTON -- The Red Sox have converted Trey Ball from a starter to a reliever and he's dominating in his new role.

Ball, the seventh-overall pick in the 2013 draft, has hurled 6 2/3 scoreless innings over three relief outings for Double-A Portland. He has allowed two hits and two walks while striking out six.

Watch out. He potentially could help Boston later on this year if he continues to progress and dominate.

The 6-foot-6, 185-pound lefty hurled 2 1/3 scoreless innings last night to earn a hold. He threw 26 of his 33 pitches for strikes. He has thrown 71 percent strikes over his three appearances. He hurled 2 innings in each of his other two appearances.

"He's left-handed so that's obviously an advantage," said Brian Bannister, Red Sox vice president of pitching development and assistant pitching coach. "And then he's developed a good cutter-slider with some power to it. Out of the pen he throws a little harder. He starts hitting those 92, 93, 94 velos, which plays up from the left side.

"But he really has just been aggressive in that role," Bannister added. "I think we've all seen him kind of thrive in it. Some guys like to have their stuff play up, they like to be out there more often. And I think it's a role he can do really well in."

He also pitched in relief during the Arizona Fall League in 2016.

Ball, who turns 24 on June 27, went 7-12 with a 5.27 ERA, 1.75 WHIP and .322 batting average against in 25 outings (24 starts) for Portland last year.

Red Sox vice president of player development Ben Crockett and minor league pitching coordinator Ralph Treuel made the decision to move him to the bullpen.

"(They) felt like it was best for him based on being around him last year," Bannister said. "And so far I think he's rose to the challenge.

"I think above all, it lets his natural athleticism shine through," Bannister added. "He was always a really good athlete. And I think he's more athletic in that role."

Ball was being scouted both as an outfielder and pitcher before the 2013 draft.

"Today's game, the lines between starters and relievers are getting so blurred," Bannister said. "It's not what it once was. I mean, you can come up here and have a lot of success pitching in multiple types of roles."