Celtic first-team coach John Kennedy has played down speculation linking defender Virgil van Dijk with a move away from the club.
Sunderland are reportedly considering an £8m bid for the 23-year-old, while Everton and West Bromwich Albion are also thought to be interested in the Dutchman.
However, Kennedy is hopeful that the centre-back will remain at Celtic Park and help the team to retain their Scottish Premiership title.
"It's speculation and that has been the case all season," he told Sky Sports News. "We got it in the summer with a lot of speculation about Virgil.
"With our top players, we expect the same every time the window opens. But until something is firm and concrete, it's just rumours, but he is a massive player for us. You see the quality he brings."
Van Dijk, who has been capped at Under-21 level for the Netherlands, joined Celtic from Groningen in 2013.