Boston Bruins center Ryan Spooner is out indefinitely with a concussion sustained in the third period of a 4-2 loss at the Ottawa Senators on Monday. Austin Czarnik was called up from Providence of the American Hockey League and will play center on Boston's third line. Czarnik had 13 points (five goals, eight assists) in 47 games with Boston before his demotion Feb. 23. "It's exciting. It's unfortunate that [Spooner] is injured, but it's my chance to try to get back into the lineup and do what I can do," Czarnik said. "So I'm just going to try and go out there tonight and try to help us get the win tonight." The Bruins are coming off a loss but are 8-3-0 since Bruce Cassidy took over as coach Feb. 7. Boston trails Ottawa by four points for second place in the Atlantic Division (the Senators have two games in hand) and leads Toronto by two points for third place (the Maple Leafs have one game in hand). Forward Drew Stafford, who was acquired in a trade from the Winnipeg Jets last Wednesday, will move up from the third line to play left wing with center David Krejci and right wing David Pastrnak. Stafford, a right-handed shot, will be playing his off wing. "I played a little left wing last year with [Mark] Scheifele and [Blake] Wheeler up in Winnipeg and had quite a bit of success. So it seems like it might be a little bit of a different game with Krejci as opposed to Spooner with some of the spots and whatnot, but we'll see," Stafford said. "It's kind of [getting thrown] right in there and see if it works, and hopefully it does and hopefully we can create something." The Bruins are 5-1-0 in their past six home games.