Kolasinac had looked like he would be moving to Juventus this month.
Juve boss Massimiliano Allegri had eyed the 23-year-old as a replacement for Patrice Evra, who left the Italian club to join Marseille.
Chelsea are keen on signing Schalke left-back Sead Kolasinac
But a deal appears to have stalled.
And now Sky Sports claim Chelsea want to bring Kolasinac to Stamford Bridge.
Chelsea boss Antonio Conte wants to reinforce his defence before tomorrow’s transfer deadline.
Chelsea transfers: Deadline day ins and outs rumours rated
Mon, January 30, 2017
Football Whispers have rated Sunderland's chances in the transfer market ahead of deadline day (1 – unlikely, 5 – likely)
1 of 7
Football Whispers have rated the likelihood of Chelsea transfer deals (out of 5)
Sead Kolasinac has impressed for Schalke in the Bundesliga this season
Branislav Ivanovic is leaving Chelsea for Zenit St Petersberg, and Kolasinac could be his replacement.
Kolasinac is out of contract with Schalke in the summer and has refused to sign a new deal.
The Bosnia international has impressed in the Bundesliga this season, and has two goals in 14 appearances.