The 29-year-old wide man, who only signed for the Owls in November after his Middlesbrough contract ended earlier in the summer, was initially believed to be under contract until the end of the season.
But sources have confirmed to The Star that his Sheffield Wednesday deal ends shortly after this weekend's trip to Oxford United and that the two parties are yet to come to an arrangement over a new deal. As it stands, this weekend's game will be his last game for the club.
It is also understood that fellow League One promotion hopefuls Wigan Athletic are among the clubs interested in signing Mendez-Laing should Wednesday be unable to strike a deal with the former Cardiff City man.
The Star believes Mendez-Laing would like to stay at Wednesday despite stuttering talks.
Speaking to the media after the Plymouth win, Mendez-Laing said: "I'd like to stay. It's a great club, a massive club. We have a great changing room, a great manager, great coaches and I'm happy here and I'm settled. My family seem to like it here as well. So why not?
"A lot of people had a lot of things to say. For myself, I feel like I do have a point to prove here.
"The gaffer was a massive factor in me coming here, how he wants to play with attacking, free-flowing football. It was a massive part of my decision to come here. It's been a pleasure working with him and long may it continue."
Mendez-Laing, who has Premier League experience having played in the top tier with Cardiff, struck a chord with Wednesday fans on Saturday with a committed and attacking display in which he unleashed more crosses and more shots that the Plymouth side combined.
He netted his first goal and first assist in the clash, after which Owls manager Darren Moore made clear his personal plans for Mendez-Laing extend far beyond January and that he would like him to stay on at S6.
He said: “He’s playing football in a team that is playing to his strengths and it was great to see him get on the score sheet."