According to the Indianapolis Star’s Jim Ayello, Indianapolis Colts starting left tackle Anthony Castonzo suffered an MCL injury to his knee against the Tennessee Titans on Sunday—although the full extent of its severity is currently unknown until he undergoes an imminent MRI:
Source: It's an MCL injury for Colts LT Anthony Castonzo. Won't know if there is cartilage damage or if the MCL is detached until he undergoes an MRI.
— Jim Ayello (@jimayello) November 29, 2020
It’s a potentially significant blow to the Colts offensive line—should Castonzo miss extended time with the injury (or really any time right now).