Celtic boss Ronny Deila says keeping his best players will take priority over acquisitions in the transfer window.
Chelsea striker Fernando Torres is understood to be set for a return to Atletico Madrid, according to Sky sources.
Stoke have announced the signing of United States international Juan Agudelo and loaned him immediately to FC Utrecht having failed to get a work permit for the striker.
The Potters completed a free transfer for the 21-year-old despite being denied a work permit in November and have decided to send him to the Eredivisie while they prepare a second application.
Agudelo, who left Major League Soccer franchise New England Revolution, made his international bow as a 17-year-old and has earned 17 caps.