Jags manager Ian McCall paid tribute to the Englishman, who has scored three goals for the club this season.
"Steve will be leaving and he does so with the best wishes of everyone at Firhill," he told the club's website.
"Since January Steve has been struggling with an ankle injury to such a degree that the player feels that it is best to go in for surgery.
"Steve feels that until his problem with his ankle has been sorted that it is impossible for him to do himself justice.
"Steve hasn't asked for any pay off for his contract being cancelled which is to his credit and to repeat we wish him all the best for the future," added McCall.
Source: BBC Sport
Source: BBC Sport