Michael Lipman has been ruled out of Bath's derby trip to Gloucester – and is no closer to knowing when he will return to action – after being told to take complete rest.

The Bath skipper was concussed during his side's Heineken Cup draw with Toulouse on January 25 – and has not played since.

He was initially named in the Bath side to face London Irish last weekend, but withdrew on the day of the match after admitting he was not right to play.

And further medical assessments have ruled that the 29-year-old should take complete rest rather than attempting to build up his training in a bid to return to action.

Bath head coach Steve Meehan said: "Michael will not be available for this weekend.

"There have been further discussions with specialists and sports medicine doctors and the thoughts are that he needs a little bit of rest, as opposed to doing a bit of training and seeing where he is at.

"It would be a much better situation for Michael if he puts his feet up for this weekend – and potentially longer. I don't know when he will be back playing, but it certainly won't be this weekend."

Meehan admitted being concerned about Lipman's ongoing issues, particularly as the player has suffered concussion on several occasions earlier in his career.

But he said the problems had not reached such a point where those at Bath were "breaking into a nervous sweat".

"There are various players in the past who have taken longer than the normal three-week protocol to come back from concussion," he said.

"If you look at players such as Richie McCaw, Leon MacDonald and Nick Kennedy, they have all been through this sort of thing.

"We just have to let it settle down and then, once the medical team is happy for him to start a little bit of exercise, we will see how he reacts and then go through with bringing him back into rugby.

"But I don't think we are at a point where everyone is breaking into a nervous sweat over it. Injuries such as this are always clouded by the fact you can't see how things are progressing.

"We have got to give it some time and see where it's at. You can't have surgery and the physios can't help; you have to let the body heal itself. Sometimes it just takes longer.

"The only description Michael has given me is that it is difficult to describe but he knows he is not 100 per cent right." Lipman's absence will be felt by Bath at Gloucester, particularly as they will also be without three other members of their highly-regarded pack in the suspended Matt Stevens, England hooker Lee Mears and the injured Danny Grewcock.

But Gloucester No 8 Gareth Delve, who spent seven years at Bath, is confident James Scaysbrook will prove an able deputy for Lipman if he is selected.

"James is probably one of the best ball-playing openside flankers outside Martyn Williams," said Delve.

"He's got a fantastic rugby brain on him and he does a lot of the unseen work.

"He's a real dog on the floor and it will be a great battle between him and Andy Hazell at the weekend.

"But he's also got a lot of subtle touches. He likes the ball in hand, he's got a good eye for the gap and a good passing game. So while they will miss Lippy, Scays is equally dangerous and has just been unlucky not to get the opportunities. I really rate him."