Cincinnati Bengals quarterbacks AJ McCarron (5) and Andy Dalton (14) talk before an NFL game earlier this year. McCarron still doesn't know what to make of a botched trade that would have sent the Bengals backup quarterback to Cleveland. The deal was reached, but all the paperwork wasn't submitted to the league before the trade deadline.

CINCINNATI — AJ McCarron was getting his son ready to Trick-or-Treat as Ace Ventura when his agent called with shocking news: The Bengals were trading the quarterback to the Cleveland Browns.

Then came another jolt: The trade fell through because paperwork wasn’t filed with the NFL office in time.

McCarron was still processing the whirlwind events Wednesday, a day after a paperwork snafu meant he’d stay in Cincinnati as Andy Dalton’s backup. The AFC North rivals agreed to the trade shortly before the 4 p.m. deadline. The Bengals say they filed their paperwork on the deal, holding up their end of the bargain.

“All you have to do is notify the league office you’re making a deal and that’s an easy thing, which we spoke to a person in there,” coach Marvin Lewis said Wednesday.

McCarron doesn’t understand how the trade was botched.

“There’s no telling,” McCarron said. “I’m lost like everybody else.”

He’ll be on the Bengals sideline Sunday when Cincinnati (3-4) plays at Jacksonville (4-3). McCarron hasn’t played this season even though Dalton has been limited by a sprained left ankle for a couple of games.

The Bengals’ agreement to trade him was an indication he’ll soon get a chance to vie for a starting job somewhere instead of remaining a backup in Cincinnati.

The Bengals had been reluctant to trade the two-time national champion from Alabama, who is in the final year of his contract. McCarron proved his value after Dalton broke the thumb on his passing hand late in the 2015 season. McCarron started the last three games, leading the Bengals to the postseason, and had them in position to win a first-round playoff game against the Steelers before Vontaze Burfict’s hit to Antonio Brown’s head moved Pittsburgh in range for a winning field goal.

McCarron was excited initially about the chance to be reunited in Cleveland with coach Hue Jackson, who was the offensive coordinator in Cincinnati. The Browns’ inability to complete the trade was the latest failure by a franchise that can’t find its footing.

Cleveland hasn’t been able to settle on a quarterback or stick with a plan. The Browns are 0-8 after going 1-15 in Jackson’s first season.

The Browns are on their bye week and declined comment on the snafu.

McCarron missed most of his rookie season with a sore shoulder. The Bengals contend that leaves him a restricted free agent after this season. McCarron thinks he should be an unrestricted free agent. The dispute will be settled in the offseason.

“I’m not angry about anything,” McCarron said. “I’m not upset. It feels good to be wanted by the team you’re on, by another team. I’m just enjoying it and when the offseason comes, however the contract dispute works out, we’ll go from there.”