The team's website posted video of the often-playful Gronkowski using the trophy as a bat before an on-the-field appearance at the Boston Red Sox's home opener April 9.
No one thought he would actually follow through on using the trophy as a bat -- until he squared around to "bunt" a warm-up pitch from Super Bowl MVP Julian Edelman.
That left a dent in the Lombardi trophy that the team might fix in the future. For now, executive vice president of media relations Stacey James said: "We're going to keep the dent and tell the story."
Gronkowski and about 20 other players were present at the Red Sox's home opener to be recognized for the Patriots' Super Bowl victory. Gronkowski threw out a ceremonial first pitch alongside Edelman and cornerback Stephon Gilmore.
As backup quarterback Brian Hoyer told the team's website, "Rob's parting gift to the organization was leaving his mark on his last Super Bowl trophy."