James injured his knee in last weekend's victory over Newcastle Falcons
South African fly-half Butch James has torn his cruciate ligament and will miss the rest of Bath's season and the summer's international action.
That means James, who has 35 caps, will not figure for the Springboks in June's three-match series against the Lions.
James sustained the injury in the 15-14 win at Newcastle and will now miss out on Bath's push for the play-offs.
The 30-year-old is set for surgery in the next fortnight and is unlikely to be back in action until 2010.
The match against the Falcons was the playmaker's 81st for club and country in a little over two years after joining Bath straight off the back of his country's World Cup success in 2007.
James had looked laboured in recent outings and his goal-kicking had drawn criticism as missed penalties cost Bath at home to Harlequins and in the Heineken Cup quarter-final defeat at Leicester.
He also missed two kicks against Newcastle before going off at half-time at Kingston Park.
But Bath head coach Steve Meehan, who has been supportive of James throughout, said: "Butch started 20 Guinness Premiership matches for us this year and seven Heineken Cup matches.
"He has played more minutes than anyone else for Bath and has done a very good job."
Ryan Davis will step into the number 10 shirt for Bath, who need to beat Saracens at home in their final match of the regular season to ensure a place in the play-offs.
James was troubled by knee problems during his time at Natal Sharks in 2002, shortly after he had broken into the Springbok side, and 2004, when a cruciate ligament injury ruled him out for six months.