Cullen, 23, is currently 11 matches into his second loan spell with the Addicks after helping them win promotion to the Championship last season.
He has been in good form for Lee Bowyer’s side, completing every minute of every game in the second-tier, where Charlton currently sit seventh in the standings.
Cullen’s form has led to questions being asked about whether he has a long-term future as a Charlton player and while the midfielder admits that he cannot make any guarantees, he is only focused right now on his future being at West Ham.
“I don’t know,” said Cullen, as quoted by London News Online, when asked if a permanent move to The Valley is on the cards.
“I can’t see my future there because I’m still on loan and I’m contracted to West Ham but football’s a strange game and you never know what’s going to happen.
“The plan has always been to get to the West Ham first team but things happen in football.
Cullen will be 24-years-old by the time his loan spell at Charlton has ended and although he has done well in League One and, so far, the Championship, is he really going to get a shot at West Ham? You would imagine that he has already reached his potential ability and the fact that he has had loan spell after loan spell away from the Hammers suggests that he is just nowhere near the first-team plans there. West Ham do have a shortage of quality in the central midfield positions. Away from Mark Noble, Declan Rice and Jack Wilshere, there’s no one there who is really that amazing. Cullen could be a fourth or fifth choice option in that area but, come next summer, the Irons may just want to sign an upgrade on someone like Noble or Wilshere rather than promote from within. It’s going to be tough for Cullen and everyone hopes that he can become a first-team regular. It just seems unlikely at the moment.