Straka sustained a concussion during overtime of the Rangers' shootout loss at Edmonton on Saturday night. Shanahan went down minutes earlier with an injured left knee after colliding with Oilers forward Dustin Penner.
Although questionable, Shanahan played against Tampa Bay on Tuesday when the Rangers returned home from their 0-2-1 trip to western Canada. The 38-year-old forward fought through the injury, described as a bruise, to notch 12:50 of ice time, but he was held scoreless in New York's 5-3 loss.
Straka is out indefinitely and certainly won't play Thursday against Philadelphia. Avery was placed on the injured list because of a bruised right hand, retroactive to the weekend.
Avery played in only seven games since coming back from left wrist surgery that forced him to sit out 11 games. He was injured in a home game against Montreal on Dec. 30 but then played in all three games of the road trip.
The Rangers recalled forwards P.A. Parenteau, Nigel Dawes and Greg Moore -- the top three scorers for AHL Hartford -- to pick up the slack. Dawes and Moore were in the lineup against the Lightning, but Parenteau sat out.