Revealed! The surprise clause in Andy Carroll's Newcastle United contract

On transfer deadline day the striker was announced as the Magpies’ fifth summer signing, on an “initial one-year deal”.

But it’s understood there is a clause in the deal that states should 30-year-old Carroll play an as yet unspecified number of games for United this season, his deal will be extended to the end of the 2020/21 season.

These kind of agreements are common place in transfer negotiations – last season Mo Diame was due a one-year extension if he started 25 games. In some cases it can be as low as 15 games.

Last season England striker Carroll made 14 appearances for West Ham United. The season previous he made 18.

Carroll is thought to be on a basic weekly wage of between £20,000 and £25,000, which is significantly increased should the player play, and, of course, score for the Magpies.

When asked last week about the make up of Carroll’s deal, head coach Steve Bruce said: “It’s all on incentives.

"With the structure of the deal the way it is that Andy signed up to, it can only be a no-brainer.

"He’s not the young Andy Carroll who left eight and a half years ago and with that maturity I hope that he can help with the younger players we've got, especially the forwards.”

Bruce sees Carroll as much more than just a player to make an impact on the park – he expects him to be a leader off it, too.

The head coach continued: "Can he be a leading light in that and help me in the dressing room to let them understand Newcastle and what it’s like to play for Newcastle? He’s got that experience in abundance.

"All of them things, just off the pitch, can be as much of a big thing for it as well as on it.”

Carroll has been pencilled in for a return date of mid-September, with the Liverpool game at Anfield – the striker’s former club – on September 14.