CHARLOTTE, N.C. — The Bucs' Josh McCown thought it was an incomplete pass. And say this about McCown: The man has a lot of experience throwing passes that don't connect with anyone.McCown, who has missed more than 50 percent of his receivers the past three weeks, launched a ball 19 yards downfield Sunday as his arm was hit by Carolina safety Roman Harper early in the fourth quarter, falling for an apparent incompletion. But the call was challenged by Panthers coach Ron Rivera, and referee Ron Tolbert reversed it, ruling it a fumble and awarding the ball to Carolina.The sack-fumble led to the last of four Graham Gano field goals and was the difference in the Bucs' 19-17 loss to the Panthers at Bank of America Stadium."No, I didn't understand it," McCown said of the ruling. "I thought my arm was going forward. Again, I don't understand how a ball goes that far downfield in that way and not … I don't know, (Harper) certainly didn't push it forward."I was throwing the ball. I felt like I threw it. I felt like he hit it as I was throwing."It was the second sack-fumble of the game for McCown, and although controversial, it wasn't as costly as the first. Leading 10-9, McCown was sacked on the third play of the second half and fumbled at the Bucs 4, setting up the Panthers' only touchdown.The loss dropped the Bucs to 2-12 and was their seventh this season in which the defense allowed 22 points or fewer, their most since 1978. If you're into silver linings, they retained the No. 1 overall pick in the NFL draft.It was another bad day throwing the football for McCown, who was 1-for-8 for 16 yards in the third quarter. He finished 13-of-28 for 154 yards with another touchdown pass to rookie Mike Evans and was intercepted by linebacker Luke Kuechly to end the game.But constant pressure — like the kind applied by Harper — has been McCown's companion. He was sacked three times Sunday, and the protection issues prompted the Bucs to make a healthy Anthony Collins inactive and flop Demar Dotson from right to left tackle before the game."We can all do a better job," coach Lovie Smith said of McCown's performance. "In the passing game, it's the quarterback and there's a lot on him. I just look to see if the quarterback is overthrowing balls, if he isn't accurate. But a lot affects that completion percentage. I thought we did a decent job when we had an opportunity to."Despite the turnovers, McCown put the Bucs in position to win the game. His zigzagging 16-yard touchdown run to cap an 80-yard drive cut the Panthers' lead to two points with 3:11 remaining in the game and three timeouts left.But the Bucs defense also had its fingerprints on the loss. On the play after McCown's controversial sack/fumble, a roughing the passer penalty on defensive end Larry English negated an interception by linebacker Orie Lemon. The Panthers continued to march for the decisive field goal.In fact, on the play before Gano's field goal, cornerback Alterraun Verner dropped an interception from Derek Anderson, who won both starts against the Bucs this season."It's 16-10 at that point, I have a chance to get the pick and get three points off the board and give our offense a chance to give us the lead," Verner said. "So it was huge. That's why I'm here, I'm supposed to make those plays."In the end, the Bucs found another creative way to lose. They averaged 6.6 yards per carry, with Doug Martin getting 63 of his season-high 96 yards on one play. But the passing game was never in synch.The most discussed play likely will be the ruling on McCown's fourth-quarter pass. Rivera said defensive assistants Sam Mills and Curtis Fuller encouraged him to challenge."The big thing was they kept yelling, 'Empty hand, empty hand,' " Rivera said. "So that meant one of our guys knocked it loose and when his hand moved forward he had nothing in there except hitting the ball with his hand, moving it forward."Former NFL head of officials Mike Pereira, who works for Fox Sports, agreed with the reversal. "Ball popped out and he pushes it — a fumble and immediate recovery by Panthers. Good win by Ron Rivera," he tweeted.But McCown and the Bucs didn't see it the same way."That's what really tilted the game, the third quarter and the slow start," McCown said. "Then we get going, and the second fumble — if that's what you want to call it — happened. So that killed us."