O'Brien's Irish Pub & Grill defied the NFL's blackout policy by displaying the web-based feed on TVs throughout the bar.
The NFL's blackout law requires home games to be sold out 72 hours before kickoff in order for them to air live on local television stations.
The NFL is looking into the matter further to determine whether owner Bernie O'Brien infringed the league's copyright.
The pub reportedly pulled in approximately 200 customers Sunday. O'Brien told the Tampa Tribune his was not the only local establishment working its way around the blackouts.
Tampa's Raymond James Stadium, with a capacity of 65,856, currently ranks 30th in league attendance, averaging 54,123 fans per home game.
The Bucs, 2-1 on the season, lost to Pittsburgh 38-13 on Sunday.