KISSIMMEE, Fla. -- Speaking with reporters for the first time since the Astros acquired hard-throwing Ken Giles from the Phillies -- presumably to be their closer -- relief pitcher Luke Gregerson was adamant Thursday he shouldn't lose his job as closer.

Gregerson, talking as his locker at Osceola County Stadium on arrival day for pitchers and catchers, converted 31 of 36 save chances last year in his first year with the Astros, going 7-3 with a 3.10 ERA. He's made more appearances (499) than any Major League reliever in the past seven seasons.

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The Astros acquired Giles from the Phillies in exchange for four players in December. He had a 1.80 ERA and 15 saves in 20 opportunities as the Phillies' closer last year and gives the Astros the power arm they need. The team hasn't said Giles will be the closer, but that's the expectation.

"I don't see any reason things should change," Gregerson said. "Obviously, bringing the guy we brought in, he's got a strong power arm and showing he can get guys out at the Major League level, and he's going to be a great addition to our bullpen no matter where we all fit in."

Gregerson on expectations pic.twitter.com/RQV0G3ykWo — Brian McTaggart (@brianmctaggart) February 18, 2016

Gregerson said the team hadn't talked to him about his role.

"We all know the situation and who we brought in," he said. "The guy's got great stuff and a strong arm. No matter where we fall in the bullpen, we've just gotten better and that's it."

When asked directly if he should be the closer even with the addition of Giles, Gregerson didn't hesitate.

"I don't see any reason why I should lose my job because of it," he said. "I was pretty happy with how things went last year. I think it could have went even better, just a few outings here and there [were rough]. We'll just move forward and see where it takes us."

Giles said Gregerson worked hard for what he accomplished and should want to remain the closer.

"He should feel that way," he said. "As of right now, I have not been told, just like you guys. I'm just here to compete and help out the team no matter what the position is."

Giles on fitting in pic.twitter.com/MFQImFjB6m — Brian McTaggart (@brianmctaggart) February 18, 2016

Gregerson, meanwhile, is dealing with tightness in his left oblique, an injury suffered a week ago while playing catch. He went on the disabled list with an oblique strain with San Diego in 2011. Gregeron's likely not going to be throwing in the bullpen with the rest of the pitchers on the first day of workouts Friday.

"I didn't want to push it and didn't want to risk doing something negative to it, so I just shut it down for a little bit and let it heal up and get back at it soon," he said. "I threw the ball light today just to keep the arm moving and felt fine. Just take it slow, and I don't see any reason why we should have any sort of setback when it comes time for the season."