William Carvalho's long-term future at Sporting Lisbon has reportedly been thrown into doubt due to a breakdown in contract talks with the Portuguese club.
The highly-rated midfielder came through the academy at Sporting and has developed into a key player for the Portuguese giants over the last 12 months.
The 23-year-old's current deal at Sporting does not expire until 2018, but it was understood that talks over a new and improved contract had long been underway.
According to A Bola, those talks have now broken down, which has alerted a number of European clubs, with Arsenal said to be the favourites for his signature.
The Portuguese international revealed last month that Arsenal were his dream club when pressed on a possible move away from his current team.
