LOS ANGELES -- Lakers guard Talen Horton-Tucker will undergo surgery to repair torn ligaments in his right thumb, sources told ESPN on Monday.

Horton-Tucker, who turns 21 next month, signed a three-year, $32 million extension in the offseason, providing the team an ascending talent among a roster mostly comprised of accomplished veterans.

The third-year wing had been the Lakers' second-leading scorer in the preseason, averaging 12.7 points on 39.3% shooting in three appearances.

It is the second significant injury to hit the Lakers before the regular season has even opened up, after Trevor Ariza required surgery on his right ankle last week. The surgery is expected to sideline him for approximately two months.

"Obviously any time you're dealing with surgery you wish for the best," LeBron James said last week when asked about Ariza. "But we believe in our docs and everyone is saying that he'll come back at full strength. So six to eight weeks, you're in a marathon. It may feel long for him but we'll welcome him coming back at 100%. We can't wait to get him back on the floor with us."

Lakers guard Malik Monk, whom like Horton-Tucker was considered to be another youthful bright spot during training camp, is also currently sidelined with a right groin strain that will be re-evaluated in a week, according to Lakers coach Frank Vogel.

"It's preseason and we have a lot of depth," Vogel said. "And we're going to have an opportunity to give minutes to other guys. Next man up."