The injury report said Gronkowski would not have practiced had the Patriots taken the field Wednesday.
This marks the first time the Patriots have acknowledged that Gronkowski sustained a concussion. He was knocked out of the Patriots' 24-20 AFC Championship Game victory against the Jacksonville Jaguars on Sunday after he took a big hit from safety Barry Church late in the second quarter and was wobbly as he got to his feet.
Gronkowski was present at the facility Monday. By the time reporters arrived in the locker room, his chair was folded up at his locker and he had left. Teammate Matthew Slater described Gronkowski as being in "pretty good spirits" when they talked.
According to ESPN's Stats & Information, Gronkowski now has been listed on the injury report 50 times over his career, but this is the first time with a concussion. That doesn't include the times he was placed on injured reserve. In 2013, when he tore his ACL on a hit by T.J. Ward that ended his season, Gronkowski was believed to have sustained a concussion on the play as well.