England number eight Vunipola only returned from three months out with a knee issue last weekend, but a wrist injury curtailed his involvement in Swansea.
Defence coach Alex Sanderson revealed during an interview with BT Sport that Vunipola – who also missed the British and Irish Lions tour of New Zealand with a shoulder injury last year – “can’t feel his wrist”, raising further questions over whether he will play a part in England’s Six Nations campaign.
Speaking after playing 70 minutes against Wasps last Sunday, Vunipola said: “It means a great deal [to come back] and I feel I’ll be better for it next week and hopefully, if I can keep going like this, I’ll be back to where I was in no time.
“It can be frustrating being injured but there can be higher powers at work. It taught me a huge lesson about looking after myself better in terms of recovery and sleep. I thought I did that better this time. Whatever runs for me, I’ll just try to smash it.
“If I can convince [England coach] Eddie [Jones] I am in the right shape and playing well enough to be picked in his squad, then great.
“I want to play for England as much as I can and I have missed it but right now my biggest focus is playing well for Saracens and hopefully transferring that on to the pitch at Twickenham.”
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