West Ham United supporters have been digesting the news that Marko Arnautovic is attempting to engineer a move away from the club this month, but the Austria international may not be the only attacker to leave before the window slams shut. 

Manuel Pellegrini has been hit by a curve-ball just at the moment in which all the right pieces of the jigsaw were beginning to fall into place in east London. Arnautovic has been integral to the Hammers' attacking endeavours in the past twelve months, bullying central defenders with his physical approach and capitalising on chances with his deadly instinct inside the penalty area.

His departure now seems inevitable after his showing against Arsenal in which he looked a shadow of his imperious best before he waved goodbye to the supporters after being substituted in the second-half.

The loss will naturally dominate the headlines this month and give the powers that be at West Ham plenty of food for thought as they scout the market for a replacement, but the club may be forced to deal with the departure of two centre-forwards before the month is over.

Indeed, while speaking on Sky Sports' Transfer Talk podcast, respected La Liga journalist Graham Hunter revealed that Lucas Perez is open to the idea of a return to Spain this month, with Real Betis a likely destination for the 30-year-old.

“Betis will have the possibility of raising their offer to West Ham.

"My information was that midweek on Wednesday, when this was being discussed in the boardroom at West Ham, there was an understanding that Lucas Perez would take the terms to play for Real Betis if a deal were agreed.

"The fact is that number one Real Betis are short of the cash that West Ham want, and number two there are other suitors.”

While Hunter's admission suggests that there is plenty left to iron out between the two clubs, Perez's stance is telling: two of Pellegrini's centre-forwards are, at the very least, open to the possibility of leaving the London Stadium this month.

With that in mind, there is no question that Pellegrini will need funds to sign at least one centre-forward before the window slams shut, but at an incredibly complicated time of the season it will be difficult for him to sign a top marksman for anything less than a premium price.

Perez has been relatively disappointing since signing for the club in the summer and his departure would not be viewed with deep regret by the supporters, but the lack of strength in depth his departure would expose is a huge cause for concern.

January is shaping up to be another busy period of transfer activity for the Hammers following their summer exploits.

West Ham fans - thoughts? Let us know below!