CELTIC and Tottenham are reportedly in talks over a potential permanent move for Cameron Carter-Vickers.

The United States defender, 24, has impressed so far in his loan spell at Parkhead this season and Sky Sports report Celtic are keen on keeping him past this season.

Included in the deal to sign Carter-Vickers on loan was an option-to-buy clause.

And Celtic are now reportedly discussing a transfer fee with Spurs for the defender with a £6million transfer demand from the Premier League club.

Sky Sports claim the talks between the clubs is on the structure of any deal, with "no-wriggle room" on the overall price.

Ex-Celtic defender Mark Wilson told the outlet Carter-Vickers is key to the vast improvement in defence for the Parkhead side this term.

He said: "I've also been really impressed by Carter-Vickers. He has improved the team in an area they needed cover.

"He was the exact type of player that was needed and his performances speak for themselves."

Ange Postecoglou has already brought in three players during the January transfer window in a triple J-League swoop.

Daizen Maeda, Reo Hatate and Yosuke Ideguchi were all announced on December 31 as Postecoglou quickly began on his mid-season improvements.