St. Louis' status is uncertain as the Lightning seek their fifth victory in six games when they host the Minnesota Wild on Thursday night.
The Tampa Bay captain became the oldest player in NHL history to win the Art Ross Trophy last season at age 37, and he's scored four goals while adding six assists since going without a point in a season-opening loss to Boston.
St. Louis trails only Sidney Crosby's 12 points for most in the league after scoring twice and adding an assist in Tuesday's 5-1 win against Los Angeles.
"He still considers himself a young kid," coach Jon Cooper said of the 38-year old.
St. Louis, though, took a shot off his foot Tuesday and is listed as day to day with a lower-body injury. Winger Brett Connolly, the No. 6 overall draft pick in 2010, was recalled from the AHL on Wednesday.
"From all indications, it's nothing that is alarmingly serious," Cooper said. "I don't want to jump to any conclusions. There's always a chance when you're day to day. We'll see what (Thursday) brings."
Cooper, though, didn't seem concerned even if his club has to play without St. Louis. Thursday's contest will mark Tampa Bay's fourth on a seven-game homestand.
"Marty will be the first one to tell you that it's not about one person," Cooper said. "You have to be ready at any moment to jump into anyone else's spot. Obviously it wouldn't be a seamless transition because of what he brings to our team, but we have enough depth that we should be able to survive."