Pharoh Cooper established himself this season as a Pro Bowl returner and a dynamic playmaker capable of making a flashy return when there sometimes appeared to be nowhere to run.
But in the first quarter of an NFC wild-card playoff game Saturday, two special-teams errors involving Cooper turned out to be costly in the Rams' 26-13 loss to the Atlanta Falcons at the Coliseum.
Cooper and Blake Countess appeared to miscommunicate on a punt return, then Cooper fumbled a kickoff return.
The Falcons recovered both.
"You've always got to protect the ball," Cooper said after the game. "I didn't do a good job of protecting the ball tonight."
Coach Sean McVay said the mistakes would not define Cooper's season.
"Certainly I think he wishes he could have a couple of those plays back," McVay said. "But I don't think it takes away from what a great job our overall unit has done throughout the year."
Special teams was a reliable, if not outstanding, unit for the Rams all season.
Cooper played a major role.
The second-year pro took over as the punt returner, in addition to already returning kickoffs, in Week 6 after Tavon Austin struggled.
Cooper excelled, averaging 12.5 yards per punt return and 27.4 yards per kickoff return. He returned a kickoff 103 yards for a touchdown in a victory over the Jacksonville Jaguars.
And Cooper was among a league-high six Rams players voted to the Associated Press All-Pro team and was voted to his first Pro Bowl.
But on Saturday, at least early, Cooper displayed only a fraction of his ability.
In the first quarter, Cooper appeared he would return a punt, then seemed to signal for a fair catch, before eventually letting the ball hit the turf as Countess charged forward.
The ball, instead of hitting the ground, bounced squarely off Countess' foot and then off Cooper, too.
Chaos ensued as the Rams tried to recover, but the Falcons fell on the ball at the Rams' 17-yard line. The defense made a stand, but the Falcons kicked a field goal to take a 3-0 lead.
"Muffed punt, hit off one of our players, that's on me," Cooper said. "I should have made the poison call."
Later in the quarter, Cooper fielded a kickoff at the Rams' seven-yard line and surveyed the field before taking off on a 21-yard return that ended with a fumble.
The Falcons recovered at the Rams' 32-yard line and scored a touchdown at the start of the second quarter to take a 13-0 lead.
"I'm going to think about it all offseason," Cooper said.
Quarterback Jared Goff credited special teams for their contributions in the Rams' division-clinching season, but acknowledged that Saturday's performance fell short.
Goff called the first muffed punt a "freak one" and said he knew that Cooper "would like to have back" the second.
But Goff did not place blame.
"They've won so many games for us, in particular Pharoh," Goff said. "They have contributed to and put us in good field position."
Against the Falcons, Cooper returned four punts for an average of 1.8 yards. He averaged 20 yards in six kickoff returns.
For his part, Countess had already endured a trying week.
The defensive back was placed into concussion protocol following the regular-season finale and also was fined $48,620 by the NFL for a hit on San Francisco 49ers receiver Marquise Goodwin. The hit left both players with concussions.