At this point in last year's schedule, Benoit gave up his 14th home run, highest among all American League relievers. Six of them either tied the game or put the Tigers behind, which is why his ability to keep opposing hitters down was a huge question heading into the postseason. He allowed a go-ahead homer to the A's in Game 2 of the AL Division Series, then settled down to not allow another run for the rest of October.
By contrast, Brian Dozier's game-tying homer Monday was the fifth home run Benoit has allowed all season. Four of them have come from right-handed hitters, though left-handed batters have had more plate appearances against him.
Benoit's 14 home runs last year were evenly split among right- and left-handed hitters. His ability to keep lefties from hitting for power is the biggest difference.