Sarries sweating on Vunipola
Saracens hope Mako Vunipola can beat a hamstring tweak to be fit for the Aviva Premiership play-offs and Heineken Cup final.
The marauding England prop was withdrawn after just seven minutes of Saracens' 44-20 Premiership victory over Worcester at Allianz Park.
Saracens withdrew the 23-year-old front-rower as a precautionary measure, with more than one eye on their Premiership semi-final in two weeks' time.
The regular-season Premiership table toppers also face holders Toulon in the Heineken Cup final on Saturday, May 24.
Saracens rugby director Mark McCall said the club will monitor the bullish front-rower's condition closely.
"Mako just tightened up his hamstring, and with the games we've got coming up we got him off the pitch as soon as we could," said McCall.
"Hamstrings are too hard to tell, he just had an awareness and we thought we'd get him off the pitch.
"We'll have more news on that in the next few days."
England fly-half Owen Farrell was once again unable to kick at goal as he continues to recover from foot trouble, with Alex Goode taking the tee duties against Worcester.
McCall backed Farrell to be ready to return to goal-kicking in Saracens' final regular-season league clash against Leicester on Saturday, May 10.
The Saracens boss also backed Charlie Hodgson to recover from a calf knock to be fit to face the Tigers at Welford Road.
"Owen's foot is fine, but it's just place-kicking that seems to aggravate it a small bit," said McCall.
"So we're just giving him a week or so without having to do that again.
"We're very confident he'll be place-kicking by the middle of next week.
"So it was just a case of getting Owen's place-kicking foot right.
"But as you saw he played pretty well apart from that.
"Alex Goode showed his class again against after showing his temperament last week in the Heineken Cup semi-final win over Clermont.
"And we're fortunate to be in the position with Charlie Hodgson's injury that we've got someone like Goodey who can step in at 10 and also goal kick."