Brett Favre says he was floored when Deion Sanders revealed this week he battled bladder cancer ... but the legendary quarterback tells TMZ Sports he's grateful Coach Prime's "prognosis looks good."
At a press conference on Monday, Sanders announced he had his bladder removed after doctors found a malignant tumor on it. Fortunately, his medical team said they caught everything in time, and the Colorado head coach is now cancer-free.
Favre -- who played with Sanders in the NFL for one season in Atlanta -- said the whole ordeal "totally shocked" him, though he couldn't have been happier to hear his old friend is going to be OK.