SAN ANTONIO -- Spurs point guard Dejounte Murray suffered a right knee injury during the second quarter of Sunday's preseason matchup against the Houston Rockets, and did not return in the team's 108-93 loss.

Driving to the basket with James Harden guarding him on a fast break, Murray winced in pain just as he planted to explode toward the rim, and crashed to the floor face down. He remained there while staffers rushed to his aid. San Antonio's medical staff brought out a wheelchair to cart Murray off the court, but the point guard waved them off.

Murray then rose to his feet as the crowd at the AT&T Center broke into applause. Murray walked off the court and headed to the locker room with Spurs medical staffers in tow.

Murray is expected to undergo an MRI on Monday, according to a source.

"He's our starting PG, and he's worked hard over the summer to get better, and I think it was showing," said Spurs forward LaMarcus Aldridge, who intended to visit Murray later Sunday night. "You just feel for him because he's worked so hard to be ready for this season."

Spurs guard Dejounte Murray grimaces in pain after suffering a knee injury during the team's preseason game against the Rockets. Soobum Im/USA TODAY Sports

While the extent of Murray's issue wasn't immediately known, the setback marked yet another injury for San Antonio's backcourt. The club announced Saturday that rookie guard Lonnie Walker IV underwent an MRI that revealed a right medial meniscus tear, which is expected to keep him out of action for six to eight weeks after he undergoes surgery Monday in San Antonio.

Walker suffered his injury against the Detroit Pistons at the 6:55 mark of the fourth quarter.

Murray, meanwhile, entered training camp with high expectations coming off a promising season as San Antonio's starting point guard, when he took over for expected future Hall of Famer Tony Parker. Murray, 22, averaged 8.1 points last season to go with 5.7 rebounds and 2.9 assists while connecting on 44.3 percent from the floor.

Murray averaged 7.8 points, 4.2 rebounds, 1.8 assists and a steal last season during the team's first-round series against the Golden State Warriors.

Internally, the Spurs expected Murray to put together a breakout campaign in 2018-19, as he's worked diligently to improve his jumper. In his first two seasons, Murray ranked as one of the worst shooters in the league, but he had shown improvement in that area over the summer working with Spurs shooting coach Chip Engelland.

"He really wants to be good. He really wants to be to the team what Tony was to the team," Spurs coach Gregg Popovich said of Murray. "I'm confident he'll do that as time goes on. But if he watched that much film all summer, it will help give him a picture. But the improvement is really made out on the court, when somebody's in front of you and trying to keep you from doing what you want to do. That's how you get better. But he's up for the challenge. We're going to let him run and take advantage of his athleticism. People will have to respond to that. Other players are going to have to run like they've never run before, because he's going to go. If they want to get the ball, they're going to have to run with him."

Several Spurs staffers privately complimented Murray on his improvement, and pointed to the third-year veteran as one of the main keys for San Antonio's revamped roster, which also now features DeMar DeRozan after the departures of Kawhi Leonard, Manu Ginobili and Parker.

"In this league today, I feel like I do a lot of great things," Murray said. "I feel I've got a lot of things I've got to work on that I've been working on. Obviously, if you can shoot in this league, knock down a midrange, a 3 here and there, then it can take you a long way; especially with the other things that I'm capable of doing. That's what I put the work in for; thousands of shots this summer, playing in open gym and getting in a little game like 5-on-5. But at the end of the day, it's confidence. I feel like I'm a confident dude. I feel like this year is going to be more exciting and better."