Kelvim Escobar’s first experience as a relief pitcher in a big-game setting was unforgettable. To this day, it’s one of his enduring memories.

“I was 21 years old, just getting started with the Blue Jays,” Escobar recalled, going back to 1997 in his mind. “It was Roger Clemens’ first game back in Boston after going to Toronto, and everybody was going crazy that day.

“I was so very nervous when I came in. I was always a starter, and I’d pitched in two games before this. It was amazing, the energy of that crowd. Roger had 16 strikeouts [and no walks] and we had a 3-1 lead. I was so pumped up I was throwing 100 miles an hour.”

Escobar went to a 1-2 count against Wil Cordero, a right-handed hitter, and got him to fly out to right field. That was the only hitter he faced that day. It took three more Jays relievers to finish the job for Clemens and preserve the victory.

Now that he knows he’s going back to the bullpen — his body having informed him in one exercise in Detroit on the recent road trip that anything beyond 75 pitches brought back the pain in his surgically repaired right shoulder — Escobar will be leaning on memories like that one to get back into a reliever’s frame of mind.

Escobar, who will begin plalying catch on Monday in San Francisco with the hope of getting on a mound soon afterward. He could become a major force in the eighth inning with Scot Shields — master of that role for the past five seasons with the Angels — out for the season with knee surgery set for Tuesday.

“It’s nothing new for me,” Escobar said. “I’ve done it before — setting up, closing, middle relief, all of it. It’s different than starting, a different challenge.

“I think once my arm is [conditioned] to relieving, I’ll be in good shape. I’ve had no problems up to 75 pitches, and I won’t need that many in the bullpen.

“It would be great for the team if I’m able to pitch down there. If I can work up to pitching back-to-back games, it would take pressure off a lot of guys. I’m very versatile. If they needed me for two or three innings, I could even do that. But probably the best thing would be one inning of my best stuff.”

Escobar’s best stuff, in any role, is about as good as it gets. He was throwing consistently in the mid-90s in Detroit on June 6, pitching five strong innings (two earned runs) but picking up the loss because Tigers right-hander Edwin Jackson was dominant.

Along with his four-seam heat, Escobar can move a two-seam fastball down in the strike zone and keep hitters guessing with a curveball, split-fingered fastball and first-rate changeup.

Coming out of the bullpen, he’ll probably rely almost exclusively on the two fastballs, changeup and curve. He’ll have no need for a slider that can cause arm strain.

“Eskie’s a great pitcher,” Shields said. “He and Darren [Oliver] are great for all the young guys on the staff with their knowledge and leadership. When Eskie’s feeling good and on his game, he’s overpowering. If he can be that guy, we’ll be in good shape.”

Escobar notched 38 of his 59 career saves in 2002 with the Jays, making a career-high 76 appearances and finishing 68 games. He last worked out of the bullpen in 2005, making nine relief appearances in a season hindered by elbow issues.