England head coach Eddie Jones will await news of Saracens' walking wounded after the Vunipola brothers were among the casualties in a bruising European Champions Cup win at Glasgow Warriors.
Mako Vunipola limped off with a calf injury and Billy later joined him on the sidelines after damaging his arm at Scotstoun on Sunday.
Fellow England internationals Maro Itoje and Jamie George suffered broken noses, while Owen Farrell and Nick Isiekwe also took knocks in a 13-3 victory for the Premiership champions.
Sarries director of rugby Mark McCall said: "Mako's is a calf injury, Billy's an arm - but it's too early to say how serious they are.
"Owen Farrell got a bang on his knee but he seemed to be okay after the game. Nick Isiekwe hurt his calf or his ankle too and that's why he wasn't able to continue on the field.
"Maro and Jamie have both got broken noses. It was a tough old game.
"Is that an unusual injury toll? Of course it is. But it is the way it is."
Jones is due to name his squad for the November internationals against South Africa, New Zealand, Japan and Australia on Thursday.
