The midfielder returns to full training with the Black Cats in a bid to prove his fitness after twice being struck down with a hamstring injury.

Top sport stories...
- Wear-Tyne derby violence - do you know these men?
- Sunderland stars treated like sheep.
- Black Cats climbing money league.
- Latest transfer rumours.
- Also on Echo.com: The web's funniest videos.

Keane has not ruled Richardson out of next weekend's trip to Portsmouth, but admits it will take a big effort from the former Manchester United man to force his way into the reckoning quickly.

The Sunderland boss has given his side a long weekend off to re-charge their batteries, though Grant Leadbitter, Danny Higginbotham and Andy Reid can look forward to some hard work in the next few days.

Keane said: "It's important that you get the balance right (in training) because we've had the injuries.

"We had an 11 v 11, which was quite hard. They will have the weekend off and than it is back to normal on Monday.

"It's short, sharp training sessions at this stage. There are 12 games to go and their fitness levels should not be a problem.

"The lads coming back from injury – Grant, Reidy, Danny next week – will do extra, but in terms of the lads who have played every week, it's just keeping them simmering nicely for next weekend."

Reid is looking to get back into his best shape after having a six-week lay-off before joining Sunderland on January 31.

Leadbitter went on as a sub in last weekend's 2-0 home win over Wigan after recovering from a broken toe, while Higginbotham should be back on the training ground next week after shaking off the same injury.

"I wouldn't have thought we'll have any of the injured players back for Portsmouth – unless Kieran trains really well next week," said Keane. "But as I've said before, we have to be careful with him."