Tom Brady did not have a very good game in his Buccaneers debut against the Saints. He averaged just 6.6 yards per attempt and threw two interceptions and generally did not look in rhythm in the game.
Where you'll almost always hear a coach explain away quarterback shortcomings in platitudes, Bruce Arians went with the direct criticism route both Sunday and today:
Bill Belichick and Tom Brady were reported to have considerable private struggles over the year, but I don't ever remember a time Belichick was this pointed in public criticism of Brady. That being said, Brady assuredly knows he didn't perform up to the lofty standards he's set in his career, and we'll all be monitoring how he responds going forward.