Bath centre Jonathan Joseph hobbled off with an ankle sprain in yesterday's 41-6 Aviva Premiership defeat to Saracens at Allianz Park.
Joseph left the field in obvious discomfort after just 27 minutes, unable to put any weight on his left foot following a collision with Schalk Burger.
England face the Springboks in June over three Tests and Eddie Jones faces a nervous wait for an update on the fitness of his first choice outside centre.
"Jonathan looks like he's given his ankle a really good tweak," Bath director of rugby Todd Blackadder said.
"We're not sure how long he'll be out for but he's got next week off anyway. Hopefully it won't be too serious."
After leaving the field on crutches, it certainly looked an injury that may threaten his participation on the summer tour, however, Blackadder remained upbeat about his chances of playing a part in the remainder of the season.