ST. LOUIS -- Injured reliever Luke Gregerson's road back to the big league mound began Saturday night, in the place where his season originally stalled.

Gregerson started a rehab assignment at Class A Advanced Palm Beach by throwing a scoreless inning against the Jupiter Hammerheads, the Marlins' Class Advanced A affiliate. Gregerson struck out two hitters, and hit a batter over a 19-pitch second inning.

Newly-signed closer Greg Holland started the game, allowing a run on two hits over a 19-pitch first meant to serve as his final tune-up before joining the Cardinals in St. Louis on Monday.

There is no specific timetable for Gregerson's assignment, and his potential return date remains unclear. But his return to game action suggests he's recovered from the left hamstring strain that sidelined him during the final week of March. Signed to a two-year, $11 million deal in the offseason, Gregerson was expected to battle for closing duties in a St. Louis bullpen that didn't include Holland, who wasn't signed until Opening Day. But the 35-year-old missed a chunk of camp due to an oblique strain, then tweaked his hamstring during conditioning drills on the final weekend of camp. The righty made just three Grapefruit League appearances.

He began the season on the disabled list, further complicating the club's late-inning alignment before it inked Holland to a one-year, $14 million deal.

Gregerson figures to factor into more of a setup role with Holland in the fold, which is where he's spent most of his nine-year career. He saved 31 games for the Astros in 2015, and 15 more in 2016, but Gregerson has made nearly three-quarters of his 623 career appearances in an inning other than the game's last. He's averaged 69 appearances per season over his Major League career.

Joe Trezza is a reporter for MLB.com. Follow him on Twitter at @joetrezz.