Bournemouth boss Eddie Howe will seek an explanation from goalkeeper Artur Boruc after he was pictured among the away fans at Rangers' Europa League clash with former club Legia Warsaw.
The 39-year-old former Celtic player was photographed holding a megaphone in the crowd at Ibrox on Thursday evening, and his presence in Glasgow came as a surprise to his manager.
Speaking at his pre-match press conference ahead of Saturday's Premier League trip to Leicester, Howe said: "I only knew about it very late last night, so it's not really ideal.
"It's something I will speak to Artur about today.
"I don't know too much about the details of it, I just knew he was there. It's something I'll be discussing with Artur today."
Poland international Boruc, who made more than 200 appearances for Rangers' arch-rivals in a five-year stay at Celtic Park after signing from Legia, joined the Cherries in September 2014 on an initial loan deal and has played 129 times for the club.
He has been an unused substitute for the first three league games of the new season with Aaron Ramsdale the current number one and Republic of Ireland stopper Mark Travers having replaced him for Wednesday night's penalty shoot-out victory over Forest Green in the Carabao Cup.
Boruc's trip north of the border ultimately ended in disappointment as Alfredo Morelos' late strike secured a 1-0 win for the home side.