TAMPA — It could be the rust. Rob Gronkowski was retired from football for a year. It’s reasonable to think he has some corrosion to knock off his game.It could be the new offense. Even in the golden age of tight ends, Bruce Arians' passing attack still runs through his wide receivers.It could be some self-doubt. Once you put your keys on the table in the NFL, it’s hard to pick them up again.Whatever the reason, the Bucs still are waiting for Gronk to be Gronk again.When Tom Brady convinced the Bucs to trade a fourth-round pick for the rights to Gronkowski and a seventh-rounder from the Patriots, they probably expected more from the 31-year-old tight end.But in two games, Gronkowski has run 33 pass routes and been targeted only four times. He caught two passes for 11 yards in the season opener at New Orleans and had no receptions in Sunday’s 31-17 win over Carolina.So far, at least, Gronkowski hasn’t been the same player he was for the New England Patriots.“We haven’t had that many red-zone opportunities, and I don’t see him running 40 yards past people anymore,” Arians said. “If we get him press coverage, hopefully he can. But we brought him in to just play tight end, and if that means no catches, it means no catches. If it means 10 catches, it means 10 catches because he’s open, and that’s where the ball goes.”All offseason, the Bucs were proud to call roll on their loaded tight end room. It’s an embarrassment of riches, a collection of players too big and strong to be covered by defensive backs and too fast to be matched up with linebackers.Despite his hiatus from football, Gronkowski already has logged a heavy workload, playing 73 percent of the Bucs' offensive snaps. By contrast, tight end Cameron Brate has played 11.Gronkowski will earn $9.25 million this season while Brate’s salary is $4.25 million. Brate has been targeted once with no catches.The statistical leader of the group has been O.J. Howard. Brady has looked his way nine times, and Howard has five receptions for 47 yards and a touchdown while playing 54.5 percent of the offensive plays.From the outset, Gronkowski has struggled.After Week 1, Arians was critical of the inability to block the perimeter, calling it a negative. “Our tight ends didn’t block the edge very well,” he said. “That was a big part of our game plan, and we got beat at it. We were out-physicaled.”On Sunday, Brady’s only pass to Gronkowski sailed over his head and was intercepted.Arians was asked earlier this week if he was surprised the Bucs tight ends — specifically Gronkowski — weren’t a bigger part of the passing attack after two games.“Not really,” Arians said. “He got a nice pass-interference call for us (and we) missed him on the over route. We’re not throwing the ball 50 times to tight ends. That’s why we have receivers for (and) that’s the way our offense is built. Gronk’s playing great run-blocking in the fourth quarter, so I’m not concerned with his pass catches or targets.”It’s odd when you consider the damage done by tight ends such as the 49ers' George Kittle, the Chiefs' Travis Kelce, the Eagles' Zach Ertz and the Raiders' Darren Waller. But the Bucs tight ends — specifically Gronkowski, Howard and Brate — aren’t more of a focal point in the passing game.The game plan will always run through Pro Bowl receivers Mike Evans and Chris Godwin, and for good reason.Arians has said he never wants to come out of a game without Evans getting at least 10 targets. That number or slightly fewer would probably be reserved for Godwin. What does that leave every other position?Outside of Heath Miller, who had 76 catches for 789 yards in 2009 when Arians was the offensive coordinator for the Steelers, no singular tight end has been a primary or even secondary target in this offense. Last season, Howard and Brate combined for 70 catches for 770 yards.Of course, Broncos coach Vic Fangio watched tape of the Bucs' first two games and sees the same old No. 87 that has caught nearly 80 touchdown passes from Brady during his soon-to-be Hall of Fame career.“I don’t think he looks any less daunting,” Fangio said of the 6-foot-6, 268-pound Gronkowski. “I think he looks like he’s in pretty good shape He’s running better than I think he did at the end of the final season of his career with New England. I think he’s healthy and raring to go. The balls have just gone outside. They have a good problem in Tampa. They’ve got a bunch of good players to throw it to. If he hasn’t gotten his yet, I’m sure by the end of the season, he’s going to have some good numbers.”Arians made it clear Gronkowski’s lack of targets is not because teams are doing more to account for him.“I don’t think they’re paying that much attention to him,” Arians said. “Tom has the ball. He decides where it’s going, so he’s reading the defenses and he’s taking whatever they’re giving him. We don’t force passes to anybody.”So why is Gronkowski back in the NFL with the Bucs?Brady wanted him, for sure. That’s a good place to start.