Oakton will be forced to try to defend its Northern Region title without Elizabeth Manner, the team’s leading scorer and rebounder. (Tracy A. Woodward/The Washington Post)

Oakton senior center Elizabeth Manner, a Stony Brook signee and the sixth-leading scorer in the Washington area, broke her thumb in the Cougars’ first-round game of the Virginia AAA Northern Region tournament on Monday night and will miss the rest of the season, Coach Fred Priester said.

The 6-foot-1 Manner, who averages 24 points and about 15 rebounds, hurt her thumb in the third quarter Monday but played the rest of the game. Late Tuesday afternoon, after X-rays, doctors determined that Manner should not try to play with the injury.

Oakton was able to regroup and win a region quarterfinal game at T.C. Williams, 46-36, on Tuesday night.

“When I gave my little pregame speech…I could see her tearing up out of the corner of my eye,” Priester said Wednesday afternoon. “She wanted to be out there so bad. But she stayed in the game and she made some good comments on the bench and made great suggestions we couldn’t necessarily make happen during the game that night but are things we can do at practice today to try to make everybody a bit more effective.”

Headed into Tuesday night, Manner had scored 600 of her team’s 1,474 points. The Cougars (22-4) will face South Lakes (22-4), which upset No. 5 Mount Vernon on a last-second shot, in the region semifinals at 8 p.m. Thursday at Robinson. The winner earns a berth into the state tournament. Oakton is the defending region and state champion.

Playoff brackets: Northern, Northwest and Region II