The Toronto Maple Leafs have moved veteran forward Joe Thornton to the long-term injured reserve. 

Head coach Sheldon Keefe announced Friday morning that Thornton will miss a minimum of four weeks with the rib fracture, while Auston Matthews is day-to-day with upper-body soreness. Both are out Friday against the Edmonton Oilers.

Thornton was injured in the third period of Wednesday's 3-1 loss to the Oilers. Keefe said after the loss it "definitely" looked like the veteran forward would miss time with the injury.

The 41-year-old is in his first season with the Maple Leafs, and 23rd in the NHL, after signing with the club in the off-season.  He has recorded one goal and one assist this season.

Matthews skated briefly before the team's practice on Thursday, but departed the ice before the team session began. Keefe said after the practice that Matthews "wasn't feeling great" coming off the game against the Oilers.

Keefe said Friday he's "not too concerned" about Matthews, with the team opting to take a cautious approach with the 23-year-old not feeling 100 per cent.

Matthews logged 24:14 of ice time in Wednesday's loss, scoring the team's lone goal. He has two goals and five points in five games this season.

With the star centre sidelined on Friday, Keefe said the team would dress 12 forwards and six defencemen, with Alexander Barabanov, Pierre Engvall and Adam Brooks drawing into the lineup. Defenceman Mikko Lehtonen is expected to exit the lineup with the team dropping back down to six blueliners.