Another 2012 NHL Entry Draft eligible has gone under the knife this season.

Calgary Hitmen defenseman Jaynen Rissling underwent surgery to repair a lower body injury in Banff, AB. Wednesday. There is no distinct timetable for his return, according to head coach Mike Williamson.

“We don’t know at this time,” Williamson said. “We don’t think it will be a long term thing but he’s going to be a couple weeks, probably.”

The significance of losing one of his top defensemen isn’t lost on Williamson, whose team has lost three of the last five games with Rissling out after winning 14 of 15.

“Jaynen logs a lot of minutes in every situation. He kills penalties. He plays against top players; plays on the power play. There are a lot of key minutes.

Rissling hasn’t played for the Hitmen since a 5-2 win on January 28th against the Medicine Hat Tigers. He joins defensemen Morgan Rielly of the Moose Jaw Warriors, Ryan Murray of the Everett Silvertips, Slater Koekkoek of the Sault Ste Marie Greyhounds and the London Knights’ Olli Maatta as just a few of the draft eligible defensemen that have missed time this season due to injury.

In 48 games this season, Rissling has three goals and 20 points.