According to Jeremy Wilson over at the Telegraph, Arsenal winger/midfielder Alex Oxlade-Chamberlain has returned from injury to take part in full training, after missing around two months with an injury to his hamstring he suffered in Arsenal's FA Cup win over Manchester United in March. He's unlikely to be available for this weekend's match against Swansea City, but should be ready sooner rather than later.
This raises an interesting issue, as the team has been clicking well lately, and while rotation is certainly necessary, Arsene Wenger may be cautious about changing the primary lineup for crucial games still to come, like the upcoming league visit to Old Trafford, and the FA Cup final at month's end against Aston Villa. The OC missed last year's FA Cup final with injury, so it would be a cool thing for him to get to play in this one. But with the season coming to a close, it's hard to tell whether there will be room for him to get enough match fitness to be at his best.
Either way, this is probably the best problem to have -- a team that's winning, and good players who are fighting to get playing time, including Oxlade-Chamberlain himself as well as Theo Walcott and Jack Wilshere.