Jimmy Garoppolo failed to register a single passing yard over three drives on Monday during his return from an ACL tear suffered 11 months ago.
The San Francisco 49ers quarterback completed only one pass over six attempts, and one of his five misfires resulted in an interception for the Denver Broncos.
Garoppolo played in three contests last year before suffering the season-ending knee injury on Sept. 23.
"Jimmy hasn't played a lot of football and then he missed last year so it's about getting him reps, putting him in different situations and letting him play as much as possible, which you wanna do but you can't just keep all your other guys out there as much as possible, too," head coach Kyle Shanahan said postgame.
Garoppolo guided San Francisco to five consecutive victories at the end of the 2017 season, giving the 49ers hope that they had found a quarterback to lead the franchise into the future. The Niners signed him to a five-year, $137.5-million contract prior to the 2018 season.