Jonathan Papelbon believes his slider is going to be a difference-maker this season. (AP)

FORT MYERS, Fla. – Jonathan Papelbon can remember the exact moment he made the commitment to his new pitch.

“I remember being in Yankee Stadium, throwing a few of them to [Mark] Teixeira and one to [Derek] Jeter,” the Red Sox closer said. “I remember throwing one to Jeter and he check-swung. He got the call – even though it was a strike – but I remember him specifically looking at me and looking like he was thinking, ‘Where did that come from?’ From then on I said I am going to start using this pitch any time, all the time.”

The pitch Papelbon refers to his is slider, and he insists it will be a difference-maker this season.

“This is the most confident I’ve felt about a breaking pitch,” he said. “It’s right where I want it to be. I’m going to throw it as much as my split. I’ll have three pitches I can throw from 0-0, to 3-2.”

Last season, Papelbon threw the pitch 111 times, compared to the 202 occasions he utilized his back-up plan pitch, the splitter. Against the slider, hitters managed a .154 batting average, compared to a .240 clip vs. the split.

The closer didn’t unleash any sliders in his first spring training outing, in which the reliever threw just six pitches. But he has been breaking it out on a regular basis during his bullpen sessions.

They have been practice pitches his fellow relievers have taken note of.

“We throw every day so I see a lot of it,” said Red Sox reliever Daniel Bard. “It seemed at times he would get on the side of it and it would have that Frisbee action and it wasn’t an effective pitch for him. The one he’s throwing this year, I don’t know if he’s gripping it different, but it’s got depth, it’s late. It looks like a plus pitch the way he’s throwing it right now. It looks like something has changed a little bit. It’s a later and sharper pitch than it was last year.”

It wasn’t as if Papelbon didn’t have a slider in his repertoire before. In ’09 he threw the pitch 107 times, it was just that hitters managed a .273 batting average when facing it. And he also had integrated into his arsenal during his days as a starter, both in the minors and then briefly in spring training of ’07.

But this time, according to Papelbon, it’s going to be different.

“I had a good slider. I had an awesome slider,” he said. “I was throwing a slider, I was throwing it a lot, but then I stopped throwing it for four years. You lose the feel for it. I’m excited about it.”