Brees made plans to see a hand specialist in L.A. The issue is believed to involve a ligament in his throwing thumb, reports NFL Network's Ian Rapoport.
The Saints initially labeled Brees questionable to return following a first-quarter exit, but he spent the rest of the game watching from the sidelines with a wrap over his right wrist and thumb. Teddy Bridgewater took over for the 40-year-old, completing 17 of 30 passes for 165 yards in the 27-9 defeat.
Brees suffered the injury hitting his hand against Rams defensive lineman Aaron Donald while following through on a throw.
He was the MVP runner-up a year ago, posting a career-high passer rating of 115.7 and leading New Orleans to the top seed in the NFC playoffs. He engineered a last-minute drive to set up a game-winning field goal against the Houston Texans in the 2019 season opener.