Arsenal and Manchester United will have to move quickly if either are going to land January target Virgil van Dijk, as Sunderland have been watching him closely and are now preparing to launch a bid for him this month.
According to the Daily Mail, Gus Poyet's scouts have been very impressed with the Celtic defender and are prepared to splash as much as £8million to try and secure his services. However, the Black Cats will have to act fast if they want to beat the Premier League giants to his signature.
Both Arsene Wenger and Louis van Gaal are reportedly on the lookout for a centre-back in the winter transfer window and Van Dijk has long been credited with being one of the names the Old Trafford and Emirates Stadium clubs have been tracking.
Celtic are reluctant to let the 23-year-old leave in the middle of the season and are in a strong position to demand a substantial fee as there are still two-and-a-half years remaining on his current deal at Park Head.
However, Premier League interest will always create problems for the Scottish giants as the riches on offer down south are far greater than they are able to offer. Sunderland could probably substantially increase Van Dijk's wages, but they would struggle to fight off any serious attempt from Manchester United and Arsenal.
Arsene Wenger's need for a centre-back has been pressing since the start of the season when Laurent Koscielny was revealed to be managing chronic tendonitis in both achilles tendons. The France international's partnership with Per Mertesacker was one of the team's strong points last season and he has been missed.
Calum Chambers was purchased in the summer as a prospective centre-back or defensive midfielder, but injuries have meant he has had to play a number of games at right-back. Wenger has also admitted the 19-year-old has played more than he would have liked, so Van Dijk would present some welcome extra cover.
Meanwhile, Louis van Gaal has extensive injury worries in his defensive ranks at Old Trafford, especially after the FA Cup win over Yeovil Town at the weekend. The Dutchman was forced to substitute Luke Shaw and Rafael at half-time in the 2-0 victory, while Paddy McNair needed staples in a head injury.
Van Dijk would provide some extra cover in the centre of defence where youngster McNair has looked shaky and the pair Chris Smalling and Phil Jones have failed to fully convince on the occasions they have been fit enough to play.
For both Arsenal and Manchester United the Holland Under-21 international would provide a sound investment. Playing for Celtic means he is accustomed to life at a massive club and the pressures it brings, while he also has Champions League experience. He is still young at 23 and, for a price in the region of £8million, could well be a huge bargain.