Mount Desert Island guard Sierra Tapley, who was a third-team Bangor Daily News All-Maine Schoolgirl Basketball selection a year ago, has been lost for the season with a torn anterior cruciate ligament in her knee.

Tapley, who earned a full scholarship to play at the University of Maine beginning next fall, learned her fate after having an MRI on Monday, according to MDI coach Brent Barker.

The 5-foot-8 Tapley averaged 16.3 points, four assists, 3.5 steals and three rebounds a game a year ago and was averaging 15 points this season.

She sustained the injury late in the second quarter of a 41-34 victory over Ellsworth on Jan. 5.

“She made a crossover move at the elbow and took a jump shot,” Barker said. “She got fouled on the arms and was a little off-balance when she landed.”

Barker said she had scored 13 points in that second quarter.

The MDI coach said she is expected to be sidelined six to nine months after having surgery. She is hoping to have the surgery next month.

Barker predicted the hardworking Tapley will do everything she can to return to the court as soon as she can.

“She’s determined, and she knows her body,” said Barker. “She hopes to be ready for training camp next fall.”

The loss of Tapley leaves Barker with a huge void, though the Trojans have beaten John Bapst of Bangor (50-47) and Mattanawcook Academy of Lincoln (51-23) since she suffered the injury.

“We aren’t going to be able to do some things we could have done with her in the lineup,” said Barker, who guided MDI to the Eastern Maine Class B championship two years ago and to an undefeated regular season and the top seed a year ago.

“We’re going to need some other players to step up and take on bigger responsibilities,” Barker said. “We’re going to spread it out.”

The Trojans lost speedy guard Darcy Kanu before the season when she transferred to a school in Texas.

“The good thing is we have a lot of young kids who have been getting experience,” Barker said. “We’re going to have to get it done collectively.”

The 9-1 Trojans host Old Town on Tuesday.