"We've got a good bullpen, and I let them know recently that Luke's going to pitch the ninth," Hinch said. "We'll sort out the other roles as we go."
Gregerson and reliever Pat Neshek were two key offseason additions to an Astros bullpen that has a Major League-high 73 blown saves over the past three seasons.
Gregerson, signed to a three-year, $18.5 million deal in December, has 19 saves in his six previous seasons with the Padres (2009-13) and Athletics ('14). In San Diego, Gregerson pitched in the back end of a bullpen that had Heath Bell and Huston Street as closers, and Sean Doolittle was closer last year in Oakland.
"It's something I've always strived to do, especially since I've been pitching late in games my whole career," Gregerson said. "I feel like the seventh, eighth, ninth innings in the game are pretty relative and pretty similar. Some days you're going to face the 1-2-3 [hitters], and some days you're going to face the 7-8-9. Our job is to get guys out."
Gregerson, 30, has pitched in 435 games over the last six years, which are the second-most most in the Majors in that span. He compiled a career-low 2.12 ERA in 72 appearances last season with 58 hits, 15 walks and 59 strikeouts in 72 1/3 innings.
"He's prepared for this role," Hinch said.
Chad Qualls converted 19 of 25 save chances for the Astros last season and has 70 saves on his resume, including 24 with Arizona in 2009. Last year, the veteran was terrific when he wasn't facing the A's (0-4, 27.00 ERA, four blown saves).
"I really could have gone a lot of different directions," Hinch said. "That's a strength of us. We have guys who are comfortable pitching late in games and getting the last three outs. I like Luke's demeanor, I like his pitch repertoire. He's having a good spring and he's very trustworthy with his pitches and how he goes about his business."
Neshek and Qualls will handle the seventh and eighth innings in roles that are yet to be defined. Right-hander Josh Fields, who's in danger of starting the season on the disabled list because of a groin strain, and veteran left-hander Tony Sipp will also pitch in high-leverage innings.
"I'm really happy how they're rooting for each other and forming a bond," Hinch said.
Gregerson relies on a heavy slider that has some deception and a fastball in the upper 80s. Hinch had Gregerson when he was with the Padres and knows he has the poise and presence to close.
"I think his steadiness has been his calling card from the first day I saw him back in San Diego," he said. "No situation raises his heart rate. He has a real feel for his stuff, and he reads swings. Those are good attributes to have out of a guy who's going to get the ball at critical times."