DALLAS — Dallas Mavericks rookie Cooper Flagg was ruled out for the second half of a 118-109 loss to Denver on Wednesday night after the No. 1 pick sprained his left ankle in the first half Wednesday night.

Flagg was called for a foul while defending against Peyton Watson, and turned the ankle as he fell to the floor with 6:01 left in the second quarter. Flagg limped to the bench and continued to the locker room, but returned for the final 2:35 before the break.

The 19-year-old didn’t come of the locker room for the second half before the announcement that he was out for the game. Flagg injured the same ankle two nights earlier, leaving briefly to get it taped before returning and leading Dallas with 27 points in a 113-105 victory over Brooklyn.

“He stepped on someone’s foot,” coach Jason Kidd said. “Last game, he twisted his ankle, too. We decided to hold him (out) for the second half.”

Kidd said he didn’t know if Flagg, who wasn’t available to reporters after the game, or center Daniel Gafford would play the second game of a back-to-back against Utah on Thursday night. Gafford was ruled out during the second half against Denver with a right ankle sprain that has bothered him most of the season.

Flagg was playing his 40th game, three more than his only season as a Duke standout when he led the Blue Devils to the Final Four as The Associated Press men’s player of the year.

Flagg missed just one game in the first 41 of the Mavericks, due to an illness in November. The Rookie of the Year contender is averaging 18.8 points and 6.3 rebounds.

Before Gafford exited, the Mavericks were already without their top two frontcourt players in 10-time All-Star Anthony Davis and young center Dereck Lively II. Davis is expected to be sidelined about six weeks with ligament damage in his left hand, and Lively is out for the season following foot surgery.

“This is a hard time for us,” Kidd said. “We have had a lot of injuries. … We have been hurt since day one of training camp. This is the norm. The character has been displayed in tough times of being down. But we keep fighting.”