Van Persie leaves Wales in protective boot
The Netherlands international was back in the United starting XI after missing the FA Cup trip to Preston North End on Monday with a knock.
Van Persie struggled to make too much of an impact in the 2-1 Premier League defeat at the Liberty Stadium and could now be facing a spell on the sidelines.
Manager Louis van Gaal did not withdraw Van Persie despite the issue, stating: "I had already changed three players and I cannot change four."
United face Sunderland in the Premier League next weekend.