The 20-year-old's season was cut short by a horror challenge from Wigan Athletic winger McManaman.
Santon told the Evening Chronicle: "My emotions are with Massadio. I'm really disappointed for him and the result.
"I didn't see the tackle but I did see Massadio's knee. It was a really bad and a lot of blood was coming out. Everybody said the tackle was really bad.
"We must win games for Massadio. I feel sorry for him. Every win is for him and Debuchy because they didn't deserve these injuries."