Per the official site:
The England winger is ahead of schedule in his bid to return to first team duty and is itching to re-join his team-mates as the season edges towards an exciting climax.
"My ankle is almost there and I'm back in training again so I should be playing again soon, all being well," he said.
"When I first picked up the injury, you are given a realistic target to aim for in terms of playing again, but it's usually longer than it will actually be. The medical team have to err on the side of caution so you take your time rehabilitating."
Johnson has certainly returned ahead of schedule and whilst the Chelsea game may well come to soon for him he is set to have a play a part on what will be an important final stretch to the season.
Despite spending prolonged spells on the bench at times this season, Johnson's absence has highlighted the lack of an alternative as direct and penetrative as him. Whilst you would expect him to spend some time on the bench in the next few weeks (rather than thrown into the starting line-up), this may be no bad thing given his effectiveness - particularly in scoring - late in games, as this recent post shows.