a medical scare on "dancing with the stars." Bill nye the science guy is on crutches and in pain after a slip on the dance floor monday night. Cameron mathison has the latest on nye's condition. Life... See More
a medical scare on "dancing with the stars." Bill nye the science guy is on crutches and in pain after a slip on the dance floor monday night. Cameron mathison has the latest on nye's condition. Life is short. Reporter: Bill nye, walking with a cane, after partially tearing ligaments in his left knee, from this paso doble on monday's "dancing with the stars." I stepped on the pant leg of my fancy slacks. Reporter: You can see him slip and then struggle a bit to lift himself. Viewers never realized his pain. You are okay? Well, yes. Reporter: Bill iced his leg, went home after the show. And yesterday, posted this picture on instagram from his doctor's office. Here's the scoop, partially torn ligament. Awaiting the doc's order with time. The doctor told us, no more. You're done. Reporter: Bill reveals to "good morning america," photos of his ultrasound. That dark section is an internal bruise. It's when this stiff edge hits the belly of the muscle, it's called. The clip went viral on youtube. It got 3 million-plus viewers. Reporter: Bill nye the science guy has an enormous fan base. But he's dancing at the bottom of the leaderboard. Our fans are pulling us through with the lowest scores in the competition. The last thing I want is to have to pull out early. Reporter: Bill and tyne aren't sure if and what they will dance on monday. But will be in the ballroom. I want to try it. I want to try to pull it off. Reporter: For "good morning america," cameron mathison, abc news. They really work. He has fans rooting for him to come back. Come on, bill. Hang in there. We love you.
This transcript has been automatically generated and may not be 100% accurate.