The Gophers men's hockey team will be without its top returning defenseman and backup goalie when it starts the season Oct. 13-14 with a series against St. Thomas.

Senior defenseman and captain Mike Koster suffered a knee injury during practice last week and will miss "a handful of weeks," coach Bob Motzko said during Thursday's media day news conference. "It's a big blow for him, a big blow for us and our leadership group," Motzko added.

Koster, a fifth-round draft pick of the Toronto Maple Leafs in 2019, is the Gophers' leading returning scorer on the blue line after scoring six goals and adding 23 assists for last season's NCAA runners-up. He was a clutch player in the postseason, collecting six points overall and four in NCAA tournament play.

Freshman goalie Nathan Airey has a lingering leg injury and will miss two to three weeks, Motzko said. Airey, a Cochrane, Alberta native, is slated to back up Justen Close when healthy.

The Gophers play host to Bemidji State for an exhibition game on Oct. 8 at 3M Arena at Mariucci. They open the season Oct. 13 against St. Thomas at Xcel Energy Center in a home game for the Tommies before facing St. Thomas the next night at Mariucci. Minnesota opens Big Ten play Oct. 26-27 with a home series against Wisconsin.