Yet the right-hander has shown the Yankees enough in his last two starts that they are still curious about what his new mechanical adjustments can do going forward.
"He's heading in the right direction," said catcher Russell Martin. "I'm sure he's feeling better about himself out there. We've been making him pitch a little bit more and not staying one-dimensional and predictable. I think it's been helping a little bit."
Burnett gave up four runs in a six-plus-inning no-decision on Wednesday -- a game the Yankees lost, 5-4, in 11 innings. He served up a two-run homer to Nolan Reimold in the third inning that he wished he could have back.
But the immediate results after a mechanical change at the suggestion of pitching coach Larry Rothschild indicate improvement, coming off an encouraging start last Thursday at Fenway Park in which he held the Red Sox to two runs in 5 2/3 innings.
Burnett now holds his hands near his chest to begin his delivery, which the Yankees believe will make it easier for him to repeat his mechanics -- something that has eluded him for most or all of his professional career, despite "stuff" that has long drawn rave reviews.
"I'll just continue to throw the ball, continue to get the ball," Burnett said. "Obviously, that's all out of our hands. We want to go out there and do our best. You pitch better, and you help out the decision a little bit. I just try to keep my rhythm, try to get back out there."
The Yankees have stayed in a six-man rotation longer than expected, and their most recent results do little to suggest that they necessarily need to make an immediate change.
"It's worked pretty well for us. It seems to keep our guys pretty fresh, too," manager Joe Girardi said. "We'll decide what we're going to do. I'm not going to commit to one way or another what we're going to do, so we'll see."