Collins has not played since the goalless draw against West Bromwich Albion back in September, when he limped off after suffering an ankle ligament injury.
The centre-half did return to play for the Hammers' Under-23 side at the end of November in an EFL Trophy match against Wycombe Wanderers, but a minor hamstring problem suffered in that game provided a further delay.
Manager David Moyes played down the possibility of Collins making a return against the Gunners in midweek, telling reporters: "James Collins is coming on a little bit as well, but he won't be ready for the game."
But contrary to those comments, the 34-year-old Wales international says he is ready to return at the London Stadium tonight.
"Buzzing to be back out there with the lads the last week or so and buzzing to be back in the squad for the Arsenal game tomorrow night," he wrote on Instagram.
Captain Mark Noble and centre-back Winston Reid returned to the starting XI for Saturday's huge victory over Premier League champions Chelsea, while strikers Javier Hernandez and Andy Carroll were unused substitutes.
Both will be hopeful of a starting role tonight with Edimilson Fernandes a doubt due to an ankle injury suffered in training on Monday morning. Cheikhou Kouyate, meanwhile, was back in full training after recovering from a hamstring issue picked up at Manchester City.
"Cheikhou has returned a little bit to training, so we're hoping we can get him back quite quickly," Moyes said. "Obviously Chicharito and Andy Carroll were back on the bench at the weekend."