"I thought Sam was outstanding today," Rhule said.
If Darnold can keep that up next week, he might enter training camp as Carolina's No. 1 signal caller.
Rhule said any discussion of potentially adding a veteran quarterback will wait until after next week's three-day minicamp, which is scheduled to run Tuesday through Thursday.
"(GM) Scott (Fitterer) and I will talk at every position and say, 'Where are we?'" Rhule said. "We've had a chance to see these guys now for eight weeks or nine weeks."
Darnold struggled mightily in his first season with the Panthers. After helping the team to a 3-0 start, Darnold reverted into his New York Jets-era form, finishing the year with more turnovers (17) than touchdowns (14).
He was also under heavy pressure, sacked 35 times in 12 games.
"Sam has to keep working and developing, we've made the offensive line significantly improved in front of him," Rhule said. "We've seen Sam get better and better and better."
The team also drafted Ole Miss QB Matt Corral in the third round, but Rhule indicated Wednesday the rookie still has a long way to go in terms of learning the offense and the pro game.
So the possibility of the Panthers bringing in a veteran QB looms.
Both Jimmy Garoppolo (49ers) and Baker Mayfield (Browns) have been excused from their respective minicamps, perhaps a sign each may have new NFL homes in 2022.
"We'll look at every guy and every guy on our team and say, 'Who is someone that we think can help us?' -- whether it be a d-lineman, whether it be a veteran quarterback," Rhule said.