Former Celtic striker Chris Sutton believes that any interested parties will keep a close eye on Virgil van Dijk's performances in the Europa League this season.
The 23-year-old was linked with a host of clubs throughout the summer, including Sevilla, Southampton and Sunderland, but a move never materialised and he will now remain at Parkhead until at least the winter.
Tomorrow night, the Dutchman will be charged with the task of nullifying the threat posed by 11-goal Red Bull Salzburg striker Jonathan Soriano as Celtic get their European campaign underway in Austria.
It is games such as that one that Sutton, who was speaking to promote BT Sport's live coverage of the encounter, has told Sports Mole will go a long way to determining if the centre-back is able to secure a switch away from his former club.
"He isn't going anywhere until January at the earliest and I'm glad that Celtic set their stool out and made their intention known to keep him during the summer. It's natural that a young player wants to play at the highest possible level and Van Dijk seems to have suggested that he does. Having said that, he owes Celtic a lot because they've given him the chance," said the 41-year-old.
"It's important that he really imposes himself on the game. He still has a lot to learn, but he has all the attributes. He is comfortable on the ball and likes to come forward, but there are times when he seems to have that Dutch arrogance and it appears that he finds the Scottish league too easy. He switched off for the goal against Aberdeen [at the weekend] and the Europa League is where he is really going to be tested.
"If he wants to be a Dutch international, which I'm sure he does, he will need to perform in the Europa League because there is little doubt that he will be tested. If potential buyers are looking at him, these are the games that they will watch him in."
Van Dijk joined the Scottish champions from Groningen for a reported £2.6m in June 2013.
BT Sport has live coverage of UEFA Europa League games throughout the group stages and beyond, including Salzburg vs. Celtic this Thursday on BT Sport 1 (not in Republic of Ireland). Visit www.btsport.com to find out more.
