"I think he can be a lot better than me," Brees said on a conference call Wednesday.
The statement came from a quarterback headed to the Hall of Fame and was made about a guy who began the season as the backup to Tyrod Taylor.
Mayfield was the first overall pick in the draft, but he has yet to throw an NFL pass. Brees, meanwhile, has thrown for 70,884 yards, completed 67 percent of his throws and won a Super Bowl in an 18-year career.
Brees, who will lead the New Orleans Saints against the Browns on Sunday, has his reasons, though.
"Man, he's got all the tools," Brees said. "He's more athletic. He probably can run around better. He's got a stronger arm."
Brees has never met nor spoken to Mayfield, though the two grew up in Texas and went to high schools that are about 12 miles apart in Texas.
"I followed his college career," Brees said. "Couldn't have been more impressed with what he was able to accomplish, especially last year. Really impressed with the way he plays the game. I think he's a great competitor."
Brees noted Doug Flutie was the starting quarterback for San Diego when he first entered the NFL in 2001 and said he learned from him. Flutie was listed at 5-foot-10, Brees at 6-foot.
Neither are prototype height for what is considered the standard for success in the NFL.
"We call it the 6-foot-and-under club," Brees said. "All the 6-foot guys kind of ... we kind of know what it's like. We kind of have the chip on our shoulder because we've heard it our whole life.
"I just kind of chuckle at it."
Is Mayfield now a member of that club?
"Well, is he 6-foot-and-under?" Brees asked.
Mayfield is listed at 6-foot-1, but he was measured at 6-foot-3/8 at the Senior Bowl and 6-foot-5/8 at the combine, so call it 6-foot-1/2.
"Well, all right, that counts," Brees said. "He's in. He's in the club."