Celtic's Janko Saidy in action with Inter Milan's Ever Banega
Janko spent last season on loan at Barnsley and he helped them consolidate in the Championship in the first season back in the second tier of English football with a 14th spot finish.
The 21-year-old, who started last season at Celtic and helped them qualify for the group stages of the Champions League, joined Barnsley in a surprise move on transfer deadline day last summer.
Celtic's Saidy Janko (R) in action with St Johnstone's Brian Easton
Janko scored on his debut for Barnsley against Wolves, but injuries restricted the attacking full-back to just 14 appearances for the Tykes.
Nevertheless Janko impressed during his time at Oakwell and his performances alerted several Championship sides.
The likes of Sheffield Wednesday, Reading and Bristol City are all looking to strengthen their right-back options for next season and they are monitoring Janko's situation at Celtic.
Celtic's Leigh Griffiths (R) celebrates scoring with Saidy Janko
Janko has returned to Celtic following his loan spell, but his first-team chances at Parkhead look limited next season with Mikael Lustig and Cristian Gamboa ahead of him in the pecking order in Brendan Rodgers' plans.
Former Manchester United defender Janko could be tempted to leave Celtic this summer in search of regular first-team football with Sheffield Wednesday, Reading and Bristol City all ready to move for the Switzerland Under-21 international.
Celtic's Saidy Janko in action against Hapoel Be'er Sheva