Red Sox closer Jonathan Papelbon is a different pitcher and a different person since he injured his shoulder last season.

The Providence Journal / GLENN OSMUNDSON

BOSTON — The determined, brisk-paced jog in from the bullpen to the mound. The Boston Red Sox cap pulled low over his eyes, the brim serving as a uni-brow.

The intense focus as he looks in for a sign. The deep breath. The right arm beginning its motion. The sizzling fastball. The wickedly dipping splitter. The fist pump that accompanies a mission successfully completed, another Sox victory in the bag.

That’s the Jonathan Papelbon the Red Sox fans have come to know over the last two seasons.

But it’s what the right-hander has been doing behind the scenes that has given him the opportunity to succeed on the mound this season. And this year, there has been a bit of a change in Papelbon, a maturity that comes not only with pitching in the same role a second season, but also borne of a serious medical scare.

Last year, Papelbon’s season ended on Sept. 1, when he suffered a subluxation of his valuable right shoulder. When his shoulder popped out, the happy-go-lucky, naturally gifted Papelbon was forced to confront his own professional baseball mortality.

“It was pretty scary. Your career flashes before your eyes,” Papelbon said yesterday before the Red Sox worked out at Fenway Park in preparation for tonight’s Game One of the American League Division Series against the Los Angeles Angels of Anaheim.

He knew what he had going. Papelbon had 35 saves in 2006, his first year as a closer in the big leagues. He was dominant, drawing comparisons to a young Mariano Rivera. While their repertoires are different, Papelbon was every bit as automatic as Rivera, the New York Yankees’ Hall-of-Fame-bound closer.

Was Papelbon going to be a one-season wonder, though? Or not even a full-season wonder?

Papelbon wondered the same thing himself.

“You don’t want to lose it,” said Papelbon of the success, fame and future fortune he was en route to in 2006.

What has transpired since has been well documented.

Papelbon, an imposing 6-foot-4, 230-pounder, recovered from his shoulder woes, working hard in the offseason to strengthen and stretch his shoulder. And, after a few sleepless nights, he begged manager Terry Francona and general manager Theo Epstein this spring to put him back in the closer’s role and forget the starting-rotation experiment Boston management had planned for him to better manage his shoulder this season.

Being used more judiciously by Francona, who has admitted that his overuse of Papelbon contributed to the shoulder problem, has worked out well for the Red Sox. Papelbon notched 37 saves in 40 chances, and generally it was game over in dominant fashion when he arrived on the scene in helping Boston claim its first A.L. East division title since 1995.

“This year worked out very, very well,” said Papelbon, the Sox’ fourth-round pick in the 2003 draft.

And that’s because Papelbon kept working out behind the scenes on virtually a daily basis.

“He had more structure to his program this year, so it was easier for him to follow,” said David Page, the Sox’ strength and conditioning coach.

“He has been dedicated, putting in the effort all year. This was a priority to him. He’s a pretty solid teammate, and this was his way of showing respect to his teammates, keeping himself prepared. He relishes that responsibility,” added Page, who, along with assistant trainer Mike Reinold, supervised Papelbon’s workouts.

Mentally, says veteran reliever Mike Timlin, Papelbon has grown, too.

“He had his ideas. We had our talks,” said Timlin, who this year became the 13th pitcher to appear in 1,000 games, including about 200 as a closer.

“[Previously], he was more concerned with relaxing and playing. This year, right from the beginning, he had a real good handle of what was going on. It’s pretty cool to watch when a [young pitcher such as Papelbon] goes from being a thrower to being a pitcher.”

Papelbon’s experiences last year, physical and mental, have helped him, says Epstein.

“He’s much more comfortable in the role this year, having gone through it last year,” said Epstein. “He knows what he has to do to be ready, and what to do between games to remain strong so he doesn’t have a situation like he had last year. He always had a good work ethic, but now he knows a little better what he has to do to make it through a season and have a good career.”

Having a routine helps. Once the game starts, Papelbon’s routine takes him from the clubhouse to the bullpen in the fifth inning. In the seventh, he begins to loosen up, stretching and jogging in the bullpen, looking like a wild stallion in a corral.

“The first two innings he’s down there he can be fairly talkative, but once the seventh rolls around, he goes off on his own and gets himself prepared to come in in the eighth or ninth,” said backup catcher Kevin Cash.

And once Papelbon gets into a game with a save on the line, the Sox and the team’s fans become very comfortable.

“I don’t think there’s any player on this team who has any doubt at all [that Papelbon will succeed],” said Cash. “We have confidence in him that he’ll get the job done. He has that confidence. You have to have that image to play that role. It’s not easy to be that successful, but even on those times when he doesn’t have his best stuff, he shows that confidence to the hitters. As a hitter, when you’re facing him, you know you’re facing one of the best, even if he doesn’t have his best stuff.”

All of which makes Papelbon well suited to succeed in arguably the most pressure-filled role on the team as the Sox begin their quest for a second World Series title in four years.

“They had a lot of [conditioning] stuff that was geared to me,” said Papelbon. “And it all pulls down to this.”

skrasner@projo.com