Willis drilled Stanton in the third quarter of Arizona’s 23-14 victory over the Niners. He was flagged 15 yards for unnecessary roughness on the play, one of three penalties on Willis. The others were for illegal contact and another unnecessary-roughness penalty for a hit on Arizona receiver Larry Fitzgerald.
"I didn't get the FedEx in the mail," Willis said, according to the San Jose Mercury News. "Maybe they reviewed it and saw it was a good hit. ... I just felt like it was in the right place."
Willis, who is nursing a wrist injury, has 20 total tackles and one interception this season for San Francisco, who lead the NFL with 36 penalties.
San Francisco plays the Philadelphia Eagles (3-0) on Sunday.
- Scooby Axson