Sam shed weight to 257 pounds coming into training camp so he’d be a viable special teams option on a team that already has a strong pass rush.
Mark Ingram had eight carries for 83 yards and a 22-yard touchdown in the first half.
"We wanted to come out here and start fast," Ingram said. "The line was just physical up front, got a lot of movement off the ball and created a lot of seams and holes for us to run through."
Luke McCown started in place of Brees, limited by a left oblique injury for a week. First-round pick Brandin Cooks caught a 25-yard touchdown pass from third-stringer Ryan Griffin in the third quarter and had five receptions for 55 yards.
"I know what I’m coming into," Cooks said. "I’m coming in with a great group of receivers. I’ve got to come in and find my spot."
Coach Sean Payton was non-committal about Brees’ chances of playing next Friday at home against the Titans.
"We’ll be smart with his recovery. He certainly is smart enough, too," Payton said. "Look, it is an area that is affected every time that you throw, so it’s important that it is 100 percent."
Bradford was held out as a precaution coming off knee surgery. Shaun Hill got the start and threw two touchdown passes in the first half.
Greg Zuerlein was barely wide left on a 59-yard field goal attempt on the final play after missing a 46-yard attempt with just under six minutes remaining.
The Rams started both of their first-round picks, offensive lineman Greg Robinson and defensive tackle Aaron Donald. Robinson, the second overall pick of the draft, started at left guard and also played left tackle.
Attendance was announced at 54,850, about 12,000 shy of capacity at the Edward Jones Dome.
The stadium appeared to be at less than half capacity not long after the opening kickoff and dwindled to perhaps one-third by the finish for the matchup between the Rams, who’ve had consecutive seven-win seasons under Fisher, and the 11-win Saints.
Chris Long, the longtime starter at left end for St. Louis, intercepted McCown on the opening series to set up Cory Harkey’s 16-yard touchdown catch.
Watch a replay of the Saints-Rams preseason game at 7 p.m. Sunday on FOX Sports Midwest
Sam began playing on the next series and made two nice plays in the second quarter, pressuring Griffin into an incompletion and getting a tackle.
"He’s unpolished like a lot of rookies," Long said of Sam. "But he pleasantly surprised you when he went out in a game situation and played pretty well."
Saints kicker Shayne Graham botched an extra-point kick from the longer distance being used the first two weeks of the preseason, hooking it off the left crossbar in the second quarter.
NOTES: Rams TE Mason Brodine fractured his left ankle and is out for the season. … Saints S Jairus Byrd, recovering from back surgery, did not play. Byrd attended high school in suburban Clayton when his father, Gill Byrd, was an assistant coach with the Rams. … Saints RB Pierre Thomas did not play because of an undisclosed injury. … Both teams hit triple digits in penalties, the Saints whistled 10 times for 104 yards and the Rams whistled 14 times for 118 yards.