HOUSTON -- Saying he had a “tough, long rehab,” Astros veteran starting pitcher Lance McCullers Jr. will make his long-awaited return to Houston's rotation when he starts Saturday against Oakland at Minute Maid Park, the club announced Wednesday.

McCullers hasn’t appeared in a game since he pitched Game 4 of last year’s American League Division Series against the White Sox and suffered a right flexor pronator strain. McCullers had a setback rehabbing from the injury in January and has spent the season building up his arm, which included 86 pitches in a rehab assignment on Sunday at Triple-A Sugar Land.

The Astros, who lead the AL in starters’ ERA at 3.18, decided to insert McCullers into the rotation, instead of giving him another Minor League rehab start, after he threw 25-30 pitches in the bullpen prior to Wednesday’s game at Minute Maid Park.

“I know it hasn’t been as long as my [Tommy John recovery], but I think, mentally, it’s more draining,” McCullers said. “There’s a lot of unknown. This injury in the postseason, the lockout and, I wouldn’t say reinjury, there was just no progress during the lockout and spring. I know I had a long road ahead of me, so I think there will be a lot of relief. I felt healthy for quite a bit now and just had to do the proper buildup.”

McCullers, who signed a five-year, $85 million contract extension in the spring of 2021 after missing the 2020 season following Tommy John surgery, went 13-5 with a 3.16 ERA in 28 starts last year, reaching career highs in wins, starts, innings pitched (162 1/3) and strikeouts (185). McCullers doesn’t expected to be limited in any way on Saturday.

“The first start back and the innings will be increased, along with the intensity, emotions, adrenaline,” he said. “I wouldn't say there’s limitations; I would say there’s a continuation of a plan, which is to get into the games and make good pitches in games and try to build that pitch count until we feel very confident with how everything is going.”

The Astros will return to a six-man rotation with the addition of McCullers. Luis Garcia will start Friday against the A’s, and he will be followed by McCullers on Saturday and Cristian Javier on Sunday. Houston traded starter Jake Odorizzi to the Braves on Aug. 2 to create an open spot in the rotation in anticipation of McCullers returning.

“I just wanted to be an active part of the team,” McCullers said. “Just step in and keep doing what this team has done so well all year, which is win ballgames and play high-quality ballgames and be a part of a team that is in position to go to another postseason.”

A healthy and effective McCullers would provide the Astros with another All-Star-caliber starter after ace Justin Verlander and lefty Framber Valdez. McCullers has pitched some of the biggest playoff games in Astros history, including Game 7 of the 2017 ALCS and World Series. He’s 2-2 with a save and a 2.83 ERA in 16 postseason games.

In last year’s postseason, he threw 6 2/3 scoreless innings in a Game 1 ALDS start against the White Sox before tossing four innings, allowing one earned run, in Game 4 and leaving with an injury.

“Last year was such a magical year for me, just because I felt like I was almost out there every time, I was going deep in games, my pitch count wasn’t a problem,” McCullers said. “It was me being out there and being a competitor and helping our team win another [AL] West title and hopefully make another deep playoff run. Obviously, it came crashing down on me in that ALDS start and it’s been an uphill battle since, but I’m glad we’re here now.”