Pitching coach Ron Guidry has been working with Rivera on a changeup, a pitch that would complement his cutter in a way his two-seam and four-seam fastballs cannot. Everything that Rivera throws always hits in the 90s on the radar gun; a changeup would cruise in at hitters in the low-to-mid 80s. Certainly no hitter could see that one coming.

"It's not something that he's going to throw a lot," Guidry said, "but there's going to be some point in time when he decides to throw one to some hitter, and it will scare the hell out of them and it will send a message to somebody else." ...

... "We're working on it," Guidry said. "He hasn't used it. I keep telling him, 'You have to use it one time.' "

Kyle Farnsworth said Rivera pulled him aside about a month ago...

"He said I need to go out there and feel like no one can hit my fastball, and to go out there, be aggressive and just keep throwing it," Farnsworth said. "He said I need to have the attitude that they can't hit it, so there's no reason to throw any other pitch."