Saracens and England centre Joel Tomkins is facing three months out of action after picking up a knee injury while on international duty.
Sarries director of rugby Mark McCall revealed the news after his side had ground out a hard-fought 16-9 victory over Exeter Chiefs at Sandy Park to maintain their place at the top of the Aviva Premiership.
Tomkins missed the trip to Devon, and McCall said: "Joel has got a knee injury, and will be out for quite some time, probably three months.
"He picked up the injury in the last five minutes of the game against New Zealand and it is a maximum 12-week injury."
Saracens were also without England fly-half Owen Farrell, while his replacement Charlie Hodgson went off with a bang to the head after only two minutes on Saturday, but McCall said they would both be fit for next weekend's home game against Sale.
"Owen is resting after three busy weeks with England, and he has played a lot for us, with Charlie not being around for the first six weeks, but he will be back for next week," McCall said.
"Charlie is fine. He got a knock on the head, and you have to be careful these days. You don't want to take any risks."
Exeter assistant coach Ali Hepher felt Exeter deserved more than just a losing bonus point out of the contest after the TMO ruled out two scores.
"We put a lot into the game and if you look at the overall game, I think a draw would have been a fair result, but it wasn't to be," he said.
"We came up a little bit short with the two TMO decisions we had, and if one of those had been given, that might have changed the game.
"We have got to take them on the chin, those decisions probably even themselves out throughout the season, but we are certainly disappointed.
"It was frustrating the referee went to the TMO for Tom's one, because we had possession of the ball, and we only needed one more phase round the corner, and we would have walked the ball in.
"We were robbed of that opportunity when the referee went to the TMO.
"Overall, we attacked the game and went after Saracens. They are probably the best defensive side in the league and we created opportunities against them, but we made a couple of errors that probably cost us."