Taylor ruptured both his anterior and posterior cruciate ligaments in Saracens Storm’s Premiership Rugby Shield opener against Exeter Braves.
“Duncan is out for the season and won’t be back until June,” McCall said.
“It’s a huge blow. He’s obviously had a poor year injury-wise. With the head injury he was never sure when he was coming back or when he was going to feel good.
“It’s cruel for one of the most popular players in the squad. It’s just one of those things.”