Brett Favre says there is one facet of Aaron Rodgers‘ Hall of Fame career that perplexes him … admitting to TMZ Sports he’s shocked the star quarterback only has one Super Bowl ring.

No. 4 sat down with us this week to break down his former teammate’s Steelers debut … and while he raved over Rodgers’ play in Pittsburgh’s season-opening win, he did relent he’s surprised there’s not some more championship bling on Aaron’s mantle.

“What I’m most surprised by,” Favre said as he reflected on Rodgers’ time in the NFL, “is he hasn’t won more Super Bowls, as prolific as he’s been.”

Nonetheless, Favre was super complimentary of the QB’s play on Sunday … noting he had told us earlier this year he just knew the signal-caller had more left in him.

Rodgers, if you missed it, completed 22 of his 30 pass attempts for 244 yards and four touchdowns in his first Steeler victory over his old Jets team … which Favre said he was super impressed by.

“The guy, and I’ve said this since Day One, he can still play,” Favre told us. “He can spin it with the best of them. The age is just a number.”

41-year-old Rodgers plays next on Sunday — in a home game against Seattle.

In addition to Rodgers’ first games in new threads, this month also featured a topic close to Favre — as Tuesday marked the 10th anniversary of the death of Tyler Sash.

Favre was featured alongside the late former New York Giant in “Concussed: The American Dream” — a documentary that shed light on the effects of head trauma in the NFL.