The Rangers shallowest position just got even more so, as the team announced that first-line center Mika Zibanejad suffered a concussion and is out indefinitely. According to coach Alain Vigneault, Zibanejad was injured when he was hit by Red Wings forward Darren Helm near the end of a game Friday at the Garden. “Didn’t seem like much,” Vigneault said after his team’s practice on Thursday, preparing for a Garden match Friday against the Hurricanes. “But my understanding is he did talk to the docs after, felt fine, was cleared.” Zibanejad continued to play that game, and even played Sunday in a 4-3 shootout win over the Canucks. But he was feeling it when he came in on Tuesday morning to prepare for that night’s game against the Panthers. He took part in that morning skate, and even took part in warmups before determining he couldn’t play. “We had optional [practice on Saturday], came in, did off ice,” Vigneault said. “Played the next game, felt fine. We had a day off on Monday and then he came in for the morning skate [Tuesday] and wasn’t feeling well. Had some symptoms. Came in the night, tried in warmup, still didn’t feel well, so we shut him down. Following the protocol.” David Desharnais was set to be a healthy scratch for that game, but got the call at 5:30 p.m. and stepped up into Zibanejad’s position between Chris Kreider and Pavel Buchnevich. Desharnais then had his best game as a Ranger, collecting three assists in a 5-4 loss.