HOUSTON — Even though the Texans were in the middle of preparations for a crucial game at Indianapolis on Wednesday, Jadeveon Clowney weighed heavily on the minds of his teammates.

Clowney (21), the first overall pick in the draft this year, underwent microfracture surgery on his right knee on Monday. Because of the severity of the surgery and the recovery period — at least nine months — he might not be ready for the start of the 2015 season.

Strong safety D.J. Swearinger, who played with Clowney at South Carolina, is close friends with the rookie outside linebacker.

“That’s tough luck to have to go through it at the start of your career,” Swearinger said. “He needs to stay prayed up and do what he has to do to get the knee back right and get back on the field. He has to stay positive about everything.”

Staying positive might be difficult for Clowney, at least at first.

He came to Houston with the pre-draft label as a once-in-a-generation pass rusher with extraordinary speed, quickness and explosiveness at defensive end. No one knows exactly what Clowney will be when he returns from a long and painful rehabilitation period.

“I’ll pray for him,” free safety Kendrick Lewis said “That’s one of my guys, one of my boys in the locker room, and I wish him well.”

The microfracture surgery followed surgery in September to repair a torn meniscus and damage to his articular cartilage.

The first operation followed a concussion in August and surgery for a sports hernia in June.

Perhaps the teammate who can identify the most closely with Clowney is inside linebacker Brian Cushing. He had season-ending knee surgery in 2012 and 2013. He also underwent surgery to repair a fractured fibula last year.

“The good thing is he’s a young guy,” Cushing said. “He’s got time to recover and get back and prove himself, turn this thing around and become a great player. The biggest thing I can do is give him support, help him keep his head up, because it’s going to be a very frustrating time.

“It’s extremely hard, especially in the offseason when nobody’s here. It’s more mental than anything, knowing how many more days and hours you have to put in with very monotonous workouts, with routines that aren’t very fun. There will also be a lot of pain involved. But you need to remember that every day you’re one step closer to getting back.”

Because of the extensive rehab process, Clowney could be ready in eight months but might take 10 months. So much depends on him and how he handles the process.

“We’re hoping to have him back for the start of the season,” general manager Rick Smith said. “We’re all disappointed, but injuries are part of the NFL. Nobody’s more disappointed than he is because he had some lofty goals for his rookie season.”

When the Texans began the season with a home game against Washington, Clowney had recovered from the concussion and the sports hernia. While rushing quarterback Robert Griffin III, he leaped into the air, landed wrong and limped off the field.

“The original injury he suffered on opening day wasn’t just limited to the lateral meniscus,” Smith said. “He also had some cartilage damage.”

Smith said the Texans knew all along that microfracture surgery was a possibility.

“Originally, we went in to clean up the meniscus and (articular) cartilage in an attempt to see if that would calm down his knee,” Smith said. “We were very diligent, but his knee wouldn’t tolerate that after the cleanup.

“We sent him to see Dr. James Andrews. When he agreed with us, we made the decision on the microfracture.”

Clowney was placed on injured reserve, ending a disappointing rookie season in which he played in four games, including two starts. He had seven tackles, including three for loss.

“It’s not about how disappointed everybody is,” Smith said. “It’s about how diligent he is in the rehab process. He’s committed to it.

“That’s something he can control, and he’s committed to showing he’s going to do everything in his power to come back and to be better than ever.”

SERIES HISTORY: The Colts lead 21-4, including 12-0 in Indianapolis. The Colts have a four-game winning streak, including a 33-28 victory at NRG Stadium in October. Quarterback Andrew Luck is 4-1 against Houston, where he went to junior high and high school.

NOTES: WR Andre Johnson didn’t practice Wednesday because he continues to undergo the concussion protocol. There’s a good chance he’ll miss the Indianapolis game. … DE J.J. Watt took a lot of grief from teammates on Wednesday when he had to wear Ohio State gear because he lost a bet with four former Buckeyes after Watt’s Wisconsin Badgers lost to Ohio State in the Big Ten championship game. “It feels strange,” he said. “I’m going to take a long, hot shower tonight.”