"He's done such a good job, I'm going to say it's a fait accompli," Rivera said after Tuesday's rain-interrupted practice. "He and I will sit down and have a conversation about it. I'm going to talk to the coaches to make sure we're all set, we're all confident, we're all comfortable.
"[But] he's done a really nice job."
If you're not as versed in French as Rivera, "fait accompli" means an it's an accomplished fact.
That Bell won the job clears up one of the biggest questions entering training camp as the Panthers looked to replace the retired Jordan Gross. Bell, who started at right tackle the past three seasons after being signed in 2011 as an undrafted rookie out of New Mexico, won the job over Nate Chandler.
"He's done some stuff on the left side that he didn't do on the right side that have been impressive," Rivera said of Bell, reminding he is a natural left-hander. "His punch is a little better, his first step is a lot better. He's working off his left side.
"Having seen that, I have confidence he can do the job for us."
Chandler will start at right tackle unless the knee injury that kept him out of Tuesday's practice keeps flaring up as it occasionally has the past couple of weeks.
"Nate has done a great job, too," Rivera said. "Look at what our lines have done in the [preseason] games. We give up a sack or two here, but the thing that has been more than anything else is we've missed some protections rather than guys have been flat-out beaten.
"That's a positive."
The Panthers also have developed decent depth with veteran Garry Williams able to back up at both tackle and guard spots. Chris Scott, whose conditioning was an issue during offseason workouts, also has done well.
Scott replaced rookie Trai Turner (groin) with the first team at right guard on Tuesday. Rivera said it was too early to tell if Turner would be ready for Friday night's preseason game at New England.
"We've got a good group of guys right now," Rivera said. "Knock on wood, we've got some decent depth."