It now looks as if the injury will keep him out for the remaninder of the season and boss Phil Parkinson was disappointed by the major blow.
"Jon has ruptured his Achilles and that's a blow for him and for the club as I thought he had one of his best games for us tonight," confirmed Parkinson.
"But when Jon went off, Matt Holland came on and did really well.
Parkinson was also full of praise for skipper Mark Hudson who had struggled since his summer move from the Eagles.
"Huds is a terrific player and a great signing for us," said Parkinson.
"I almost feel he's been frustrated recently and that's showed in his performances. Tonight he did the job as a centre-half which is what we want from him. He's such a great lad that he's almost been trying to do other people's jobs on the pitch. He's a captain and he leads by example."