"Yeah," Doolittle said, "I was trying not to smile."
Maybe so, but he deserved to grin.
Mastering the pitch has consumed Doolittle's days since he rediscovered it while throwing a bullpen session at his alma mater, the University of Virginia, just a few weeks ago. On hand for an annual baseball banquet, Doolittle threw in front of pitching coach Karl Kuhn, who wondered why his former student wasn't utilizing a slider anymore.
After all, it was one of his best pitches in college, before he became an everyday first baseman in the Minors and made the switch back to the mound again in 2011.
"I threw one, and I said, 'Let's do that again,'" recalled Doolittle. "The main thing was the mindset about how to throw it. Having been a hitter, I know what a nasty slider looks like. So I got myself in trouble by trying to make it too nasty. We just kind of needed something that had a little bit of depth that slides at the very end. I don't need a power slider. I don't think that will be something I'll ever have.
"I threw seven, and like five were the best five sliders I've ever thrown. Since then, I've been doing that every day so I don't lose it."
Consider it a big weapon for the 27-year-old Doolittle, mostly a one-pitch guy since his arrival in the big leagues. But even as one of the best young relievers in the game, his 94-mph fastball was getting lonely.
Adding another pitch couldn't have come at a better time, since he's now been in the league long enough to watch opponents make adjustments against him.
"You have to counter that some way," Doolittle said. "It's been no secret that I'm attacking with my fastball. I feel like I can still be effective with it by the way that I can move it around, but at some point you're going to leave one out over the plate and it's going to catch up with you. To have something to put in the back of their minds, and not just something that can keep them off balance but can really be effective, could mean a lot for me.
"Rather than have a guy foul off six fastballs, I can go to the slider or changeup and have shorter innings and stay fresher longer in the season. I'm becoming more of a complete pitcher instead of just a thrower."
"He's doing things that will make him better over the course of a year," said manager Bob Melvin. "There are scouts in the stands watching this. If hitters have any doubt what he's throwing, it'll make his fastball that much better, and he realizes that."
Doolittle threw something of a slurve last year, since he could never quite figure out the slider, but even that proved ineffective, since it was "big and loopy," as he said. He had to strictly throw it in situations where it could be a surprise pitch, and it better be buried in the dirt against a lefty, or else.
Now, his slider can break off the plate for a swing-and-miss or weak contact.
"It's come a long way, and it's been something I've been able to repeat over and over again in my side work and live BPs," he said. "There was a time where whoever was catching would put the slider down, I'd think, 'Well, I'm not going to get beat with this, so I better put it in a spot where it's going to be a swing-and-miss or in the dirt.' Now, I think it's a pitch where I'm more in attack mode when they throw it down, so I'm definitely gaining confidence in it."
Doolittle's also more confident in his changeup than he was a year ago. He only threw it once Friday but plans to mix it in with his other two pitches as the spring schedule chugs along.
"Your first outing," he said, "you don't want to do a guy a favor and hang him a changeup in Arizona. But I think that's going to be something I go to more as well. It was definitely a positive first day."