Tom Brady's BFF, Rob Gronkowski, is retired ... so TB12's taking his hunt for new offseason workout partners to UCLA!!!
The GOAT joined the Bruins for an impromptu throwing sesh Wednesday morning ... and seems the Patriots QB enjoyed it -- he smiled and took pics with all the guys afterward.
Of course, this is becoming an annual thing for the NFL superstar ... just 12 months ago, Brady was in town and ran an entire workout with the Bruins' offense.