Arsenal will have no reinforcements for the vital, possibly title-defining match with Leicester on Sunday, but Danny Welbeck, Jack Wilshere and Santi Cazorla are all on the way back. Welbeck played an hour with the U-21s last week, and could be involved with the squad that plays Hull City in the FA Cup next week--putting him in line to be involved against Barcelona in the Champions League.
Jack Wilshere and Santi Cazorla are still out for the foreseeable future, but that future is no longer months, with both, according to Arsène Wenger, on a fitness programme and back running. For them, "it is a question of weeks", though Wenger is predictably vague about that length of time. Given Cazorla was meant to be back in March, and Wilshere was recently reported as being out for another 6 weeks, a return date of mid-March seems reasonable.
Tomas Rosicky is out, of course, and may not play again for Arsenal as his contract expires this summer.