Day suffered a double fracture of his right leg, an injury sustained when he raced from his line to make a clearance, and QPR boss Ian Holloway (pictured) has admitted that it is a massive blow to the club.
Speaking about the incident which saw Day stretchered from the field, Holloway said: "There was some terrible play leading up to Chris being forced to race out of his area to clear. We shouldn't have got into that position, it was a short backpass and fortunately for us he was quick off his line otherwise we would have been a goal behind. But I would rather have lost the game than lost him.
"It's a real blow. It looks as though both bones in his leg have been fractured. He's been playing so well. When we took him in the summer I don't think many clubs wanted him, but he's proved to be one of the best keepers in the division."
Day has established himself as the number one at Loftus Road this term, but is likely to miss a substantial chunk of the season, with Fraser Digby set to fill the void.
QPR suffered a second injury setback against The Latics, with striker Dominic Foley, on loan from Watford, picking up a hamstring strain that could force him out for a number of weeks.
Holloway said: "Dominic Foley looked good when he was on, but when he fell from leaping for a header he tweaked his hamstring so we don't know how long he will be out for or if he will return to Watford.
"At the start of the season things were going for us, but now that's changed. The important thing throughout this is that we keep together and work as a team."
