They were taken during the Patriots' bye week.
Gronkowski, who is having an outstanding year in his second NFL season, met with team owner Robert Kraft afterward. Gronkowski said Wednesday that being in the pros is a learning process.
"I didn't intend anything to hurt the reputation of anyone on the New England Patriots or on behalf of Robert Kraft," he said. "It was just a simple picture and that's all."
Gronkowski is hardly the first pro athlete to be in Jones' company. Jones (real name Britney Maclin) told a Boston radio station and businessinsider.com this week that a sports agent in Arizona regularly introduced her to major league baseball players last year as the agent tried to recruit potential clients.
She said she enjoyed meeting the players and was never paid for her time. She didn't identify the agent.
"(The agent) would just take me to a bar and introduce me after a Diamondbacks game in Arizona," she told businessinsider.com. "You know, baseball players would come and I’d introduce myself. And then I got to hook up with baseball players and have fun. It was like a dream come true because I love athletes and baseball’s my favorite sport."
Jones claimed that she slept with "more than 10" players, adding that "a couple" of them may have later signed with the agent. She told the Boston radio station she had encounters with Atlanta Braves second baseman Dan Uggla and Phoenix Coyotes player Paul Bissonette (Bissonette has denied Jones' claim).
She said she ended her association with the agent because "I got into a relationship and it was hard to explain why I was going out every night."