For years, the book on A.J. Burnett has been high-velocity fastball and a curve that sometimes comes with a devastating hook.

When you’ve gone 10-15 relying on those two things, there comes a time to evolve or change it up slightly. For Burnett, his recovery this year might be contingent on the development and success of the changeup - a pitch that is designed to compliment his primary pitches.

Yesterday Burnett threw 12 changeups - primarily to lefties and that doubled his total he threw in five innings against the Detroit Tigers Saturday.

Last year, Burnett threw 3,175 pitches and just 84 were changeups. In 2009, he threw 4,117 pitches and just 77 were changeups.

Three years ago as an 18-game winner with the Toronto Blue Jays, Burnett threw 3,530 pitches and 130 of those were changeups.

In winning his second game, Burnett did not use at as an out pitch, but one to set up the next pitch. At least if you’re basing it on these examples, such a 1-1 changeup thrown to Jason Kubel in the second.

Kubel fouled that pitch off and then struck out swinging on a curve that clocked in at 82 – six miles slower than the previous pitch.

When he faced Joe Mauer a second time with Denard Span on third following a wild pitch, he threw the three-time AL batting champion two changeups. The first was a 1-0 pitch that was a swinging strike and the next was a 3-1 pitch that was a called strike setting up the four-seam fastball that struck Mauer out looking.

"I came in and I asked Larry (pitching coach Larry Rothchild), 'Did I throw Mauer a 3-1 changeup?'" Burnett said "And I did. I've said all along it's a big pitch for me, and hopefully this year I can use it more.

The next time he faced Kubel with Jim Thome on third and one out in the fourth, Burnett threw three changeups all at 88. At 1-1, the third changeup went past Mark Teixeira and into right field for a double.

After that, Burnett threw the pitch four more times for two foul balls and two balls, but even with limited use catcher Russell Martin said it was his best pitch and this is what he felt made it his best pitch yesterday:

"His changeup is a good pitch, especially when he’s keeping his fastball down in the zone. It comes off the same plane. It is a few miles an hour different – just enough to get the ball off the hitters’ barrel.”

The obvious angle from a pitching standpoint would be to focus on Rafael Soriano’s rebound in the eighth inning, but keep this in mind: Soriano might not get that opportunity if Burnett does not pitch well with his changeup and other pitches.

"It gave them something else to look at, and that's the importance of having another pitch," manager Joe Girardi said. "You can't maybe sit on one pitch. Now you've got something slow going away from you as opposed to coming in to you against those left-handed hitters, and I thought that made a difference."

Whether it makes a difference over the course of six months and 30 or regular-season starts is up to Burnett.