The junior center was on crutches Wednesday - his 22nd birthday - between rehab sessions for his injured left knee. Stainbrook strained the medial collateral ligament during the first half of a 71-62 loss at Seton Hall on Monday night.
The injury isn't as serious as Stainbrook initially feared. He thought he tore a ligament when his knee buckled.
''It was horrible,'' Stainbrook said. ''To me, it was devastating.''
Although tests detected only a strain, he'll be sidelined for Xavier's final regular-season game on Thursday against No. 6 Villanova. The Musketeers (20-10, 10-7) are tied with Providence for third place in the Big East.
Xavier was hoping to finish the season strong. The Musketeers ended February with a 65-53 win at St. John's and beat then-No. 9 Creighton 75-69 at the Cintas Center last Saturday. Two days later at Seton Hall, they lost their top rebounder and third-leading scorer in the first half and never got into a flow on offense.
''We obviously laid an egg when we went to Seton Hall,'' senior forward Isaiah Philmore said. ''We didn't do what we were supposed to do.''
And they don't have much time to get ready to take on one of the nation's top teams without their best front-line player. Villanova (26-3, 14-2) leads the Big East by one game over Creighton.
Philmore was glad to see Stainbrook moving around on crutches Wednesday instead of preparing for knee surgery.
''It was definitely a relief,'' Philmore said. ''At the same time, we don't know when he's going to be coming back. It would have been better if we found out there was nothing really wrong. I'm happy he doesn't need surgery, that's for sure.''
Stainbrook will have a week to heal before Xavier's first game in the Big East tournament. Trainers have told him there's a possibility he could be ready for it.
''That's what I'm hoping,'' Stainbrook said. ''It's something I'm very optimistic about. They said it depends, it's all different for different people. It's hard to tell.
''I'm feeling a ton better, even small strides from yesterday to today. I'm pedaling the (stationary) bike saying, 'There's no pain today.'''
The Musketeers lost at Villanova 81-58 on Feb. 3, letting the Wildcats blow open a close game in the second half. Stainbrook had 14 points and 11 rebounds in that game.
The 6-foot-10, 260-pound center is second in the Big East with 7.8 rebounds per game. He ranks third in the conference in both offensive rebounding and defensive rebounding. Xavier leads the Big East in rebounding margin.
He's also third on the team in scoring with 10.6 points per game. He's good at passing to an open shooter on the perimeter when defenses double team him.
''He's very versatile,'' Philmore said. ''Now we need people to step up and score points because he was a big contributor in that aspect.''
Freshman Jalen Reynolds will move into his role. The 6-foot-9, 222-pound forward has grown into a bigger role off the bench during conference play. He tied the school record for rebounds by a freshman with 16 in the win over St. John's - along with scoring 17 points - and had nine rebounds against Creighton.
''The good thing is Jalen has played very well here of late,'' coach Chris Mack said. ''He's not going to have the experience that Matt brings to the table, but he's more athletic, he rebounds every bit as well as Matt does and we feel he's a capable scorer as evidenced by a few games he's had this season.''
Early in the season, Reynolds was prone to get into foul trouble. He played a season-high 29 points in the win at St. John's while picking up two fouls. He had four fouls in 22 minutes of the win over Creighton.
''He's a much different player than he was to months ago,'' Mack said. ''It's a great thing for our team.''
Stainbrook will be on the bench, wearing a bowtie and rooting during the game on Thursday.
''I've had a couple guys text me and say, 'Hey, we're going to step up,''' Stainbrook said. ''I have a ton of faith in my teammates, specifically the big guys. I'm excited for Thursday. I'm ready for those guys to get their chance to shine, and I think they're ready.''
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