For the season, he is 1-0 with a 1.84 ERA in 16 appearances.
"Over the last year-plus, he's been equally good against right-handers and you can make the argument he's been better against them," said Red Sox manager John Farrell. "His breaking ball has tightened up. Most importantly, he's thrown a high percentage of strikes and that's been the case since probably outing No. 4 this year and to date."
While control was once a major issue for Miller, he has been pounding the zone of late.
"I think there was a time before the foot injury last year, he was on an equal run," Farrell said. "We have a little history, so we know it takes him that first three weeks of the season to kind of let things click or two weeks of the season before it clicks. He simplified his delivery. He's pitching with a lot of confidence. He can miss bats and he can get away with pitches in the middle of the plate because he's a mid- to upper-90s kind of guy. He's got a lot going for him."