"It's extremely disappointing for us in the position that we are in," said Allardyce.
"He has just come back into the fold and started to show the talent against for us, he has got and playing to the best of his game and, sadly, that's now going to be missing from now until the end of the season.
"It's going to be a big loss for it. After all his injury problems, we finally got the Ivan Campo back that we all know and love.
"He has shown it in the last two games. He gave us a different dimension with his passing that we don't quite get otherwise.
"His contract is a difficult subject to address at the moment but, of course, it needs addressing and me and the chairman need to sit down as quickly as possible to make a decision now, one way or the other, regarding Ivan.
"That will happen in the near future."