Lewis will spend the rest of the season with Bath

The club are keen to finalise their squad for the Heineken Cup, with the registration deadline on Friday.

Lewis, 29, won 16 caps between 1998 and 2001, and has played in the Heineken Cup with Pontypridd and Swansea.

Bath director of rubgy Jack Rowell said: "We required another quality back-row player, as we felt that there was not sufficient cover."

He added: "Geraint was very impressive for Rotherham throughout last season, and as an experienced Zurich Premiership campaigner he will hit the ground running as we enter what is a very crucial part of the season."

He is a great addition to the squad Bath coach, John Connolly

Bath, the European champions in 1998, have been drawn with Leinster, Bourgoin and Treviso in this year's pool.

Head coach John Connolly is confident the club have made a shrewd acquisition for this term.

"Geraint stood out last season for Rotherham as a very good ball-carrier, and was probably their best and most consistent player in what was a difficult campaign," he said.

"He will provide us with valuable experience and cover in the back-row.

"With a tough campaign of Heineken Cup and Zurich Premiership rugby to play this season, he is a great addition to the squad."

Lewis' agent Peter Underhill says the move could reignite the player's career.

"This is a great move for Geraint, playing for a club like Bath will provide him with the platform to show that he still has a lot to offer at the very highest level," Underhill told BBC Sport Wales.

"If you know where to look then there will always be clubs wanting to sign quality players."

Lewis knows that the challenge at Bath will be tough, but hopes to make an impact that could reverberate on the international scene.

"I realise it will be difficult to break into the side as they do have quite a settled back row," said Lewis.

"I'll never give up on trying too break back into the Welsh side.

"I do feel that as time goes by my chance is getting smaller, but it can only help being involved with a club like Bath."