Stamkos is sitting out a four-game post-Olympic trip that starts Thursday at Nashville.
Stamkos underwent X-rays on Monday that revealed that his broken right shin, which has sidelined him since November, is improving but not enough for him to be cleared to play in games.
The centre will travel with the team to continue practicing, and is expected to be examined again when the Lightning return for a homestand that begins March 6 against Buffalo.
Stamkos was injured on Nov. 11 at Boston and underwent surgery. He has 14 goals and 23 points in 17 games this season. The injury kept Stamkos from playing for Canada in the Sochi Olympics.