Johnson spent his first five NFL seasons with the Arizona Cardinals, catching 210 passes for 2,675 yards and nine touchdowns. He was the club's third receiver for much of that time behind Pro Bowl selections Larry Fitzgerald and Anquan Boldin, but could be a starter in San Francisco.
"Bryant is a young, talented player," 49ers general manager Scot McCloughan said. "He brings big-play capabilities to the offense, and we feel he will bring in an added dimension to the talent we already have on board."
The 49ers have had one of the NFL's most unproductive groups of receivers since Terrell Owens' departure four years ago, but McCloughan has taken another shot at filling that void this spring. San Francisco also signed Isaac Bruce, who spent his first 14 NFL seasons in the NFC West with the Rams, shortly after the start of free agency.
But the 49ers also released Darrell Jackson, who caught 46 passes last season, on Saturday after just one season with the NFL's least productive offense. Veterans Arnaz Battle, who had 50 receptions for 600 yards to lead the team's wideouts, and Ashley Lelie are expected to return next season to San Francisco, and the club is likely to add a receiver in the draft to provide more options for Martz and his pass-happy scheme.