Allen, 34, has 351 yards and one touchdown on 40 receptions through eight games with the Colts this season. He'll now be joining fellow veteran Mike Evans on a 49ers team that leads the NFC with a 7-1 record.
Allen will bring solid depth to a 49ers wide receiver core banged up by injuries, including Evans, Deebo Samuel Jr., Ricky Pearsall (IR - out for season), and De'Zhaun Stribling (IR).
Evans (Achilles/rib) has missed the last two games; Samuel (hamstring) the last three. Stribling (ankle) is eyeing a return in December.
He'll join the team as they get ready for their Sunday matchup against the Dallas Cowboys.
Allen has spent eight of his 10 years in the NFL as a member of the Los Angeles Chargers, eventually becoming the franchise's all-time leader in receptions (985). The vet, known for his incredible route running and hands, went to the University of California, Berkeley (aka 'Cal'), which is located in San Francisco.
Now, he'll join a Super Bowl contender as he seeks his first-ever ring.
Through 179 games, Allen has posted 1,095 receptions, 12,402 yards, and 71 touchdowns.
National Football League
Follow along with Flashscore's coverage of the NFL as the regular season is underway!
NFL news and updates | NFL standings | 2026 NFL Season Guide