ST. LOUIS — Freak injuries to forwards Alex Steen and Andy McDonald just seconds apart during battle drills at practice Tuesday left the St. Louis Blues in an unfortunate and all-too-familiar situation.

McDonald was placed on injured reserve with a left knee injury Wednesday and is "week-to-week," according to Blues coach Ken Hitchcock. Hitchcock said Steen has an upper-body injury and is day-to-day, but the coach refused to rule him out for Thursday's game against Chicago.

A year ago, McDonald missed 57 games with a concussion and shoulder injury while Steen missed 39 games with a concussion.

Steen leads the Blues in scoring with four goals and 16 points in 18 games, while McDonald has three goals and 11 points.

"It happens and we've got lots of guys that are coming in that are hungry, guys that have played in the NHL, so we shouldn't miss a beat," Hitchcock said. "I can tell you there's guys champing at the bit that want more, so somebody's demise is somebody's opportunity. Then you never know where a guy runs with it."

The injuries opened potential lineup spots for Blues forwards Chris Porter and newcomer Andrew Murray. Murray, who played for Hitchcock previously in Columbus, was recalled Tuesday from Peoria under emergency conditions.

The Blues on Wednesday recalled forward Adam Cracknell from Peoria. The 31-year-old Murray has NHL experience with San Jose and Columbus.

Blues defenseman Kevin Shattenkirk said McDonald's absence creates a hard spot to fill.

"It's tough because he makes everyone better around him," Shattenkirk said. "If you look at last year, he came back and our power play started flourishing because of him and the work that he does there. You feel so bad for him because he works hard every day."

Porter was recalled last week after the Blues lost rookie winger Vladimir Tarasenko to a concussion.

"We're a deep team, we have players that can move up and down the lineup," Blues center Scott Nichol said. "It's going to be a challenge, but we rise to the challenge all the time in this room. It's fun to be challenged and pushed and see how we react."

How will injuries to two of the Blues' top forwards affect the team?

"It was gone after an hour last night," Hitchcock said Wednesday. "As soon as everybody finds out the information, everybody's moved on. Guys go down in practice, guys go down during games, it can happen any time. ... Guys get the flu.

"The unknown injury is Tarasenko, because we don't know a date. The other guys, it's really defined."

At practice Wednesday, the 28-year-old Porter played left wing on a line that included Jaden Schwartz and Chris Stewart. Schwartz moved to center, a spot he has played previously both at Peoria and while in college.

"He's looking for an opportunity to get more ice time and more responsibility, well this is it," Hitchcock said of Schwartz, "He's got a real opportunity, as does (Matt) D'Agostini as does Porter."

Porter, a speedy checking winger who has played parts of three seasons with the Blues, was the last player cut during training camp. He had seven goals and 10 points in 12 games at Peoria.

"I think the guy that's hungry is Porter," Hitchcock said. "I'm curious to see how 'Ports' plays. He's a cut above most guys in the AHL, he's a dominant player down there."

Steen centered McDonald and Tarasenko at the start of the season and now the entire line could be out. Tarasenko had six goals and 12 points in his first 17 NHL games and is out indefinitely.

"We still have a lot of skill," Hitchcock said of Steen and McDonald. "It's not like these are six-week or four-week injuries, these are short-term injuries. We've been lucky so far; we've got three or four quality forwards out, but everybody's got that going. We haven't lost any defensemen."

Porter wasn't happy the Blues had injuries, but he appreciates another opportunity.

"Everybody's going to be disappointed getting sent down, but I didn't take it as a negative," he said. "I went down and worked as hard as I could and now that the opportunity's here, I can hopefully stay here."

Hitchcock appreciates Porter's willingness to work.

"This is why he signed with us, because he trusted management and the coaching staff," Hitchcock said. "He could have signed with 10 other teams and taken the same deal. He signed with us because he knew he'd get the opportunity and when he got it, he'd take advantage of it.

"When you're down there and you're dominating like he is, you know that you can help."

Contact reporter Norm Sanders at 239-2454, nsanders@bnd.com or on Twitter @NormSanders