The Trinidad and Tobago striker, signed for £8million from Sunderland in the week, fell awkwardly under a challenge from Jody Craddock.
The 25-year-old was due to undergo a scan on his ankle today.
Potters midfielder Michael Tonge, who featured as a second-half substitute, said: "I'm a gutted for him. He started really well and hit the bar. If that had gone in it would have been a different game.
"Kenwyne on top of his game will be a handful for any centre-half in the league."