Vladimir Tarasenko isn’t the first young NHL player to leave the lineup with a concussion this season. He’s the latest – and it’s big-picture problem for the league, according to Blues coach Ken Hitchcock. Tarasenko was the recipient of a head shot delivered by Colorado’s Mark Olver in the third period of Wednesday’s 1-0 overtime loss to the Avalanche. On Friday, the Blues placed the rookie winger on the injured reserve list. “He’s got a pretty severe facial laceration (and) some form of concussion,” Hitchcock said. “We really don’t know yet … the severity of it. He didn’t have a headache (Thursday), but he did have a headache (Friday). We’ll see in the next 48 hours how much better he gets.” At a minimum, Tarasenko will miss tonight’s game against Columbus. With his placement on the seven-day IR being retroactive to Wednesday’s game, Tarasenko would be eligible to return Thursday against Chicago. But as the Blues know first-hand, it’s way too early to predict the absence of a concussed player. In the meantime, the Blues will put Matt D’Agostini in Tarasenko’s spot in the lineup, and the club has called up forward Chris Porter from Peoria, where he had 10 points (seven goals, three assists) in 11 games.