The 49ers announced their trade for wide receiver Skyy Moore from the Chiefs for a swap of late-round 2027 picks.
The team placed cornerback Tre Brown on injured reserve in a corresponding move.
The 49ers signed Brown in the offseason to help replace all their losses in the secondary. Brown, though, had fallen behind Dallis Flowers on the depth chart.
Brown, a fourth-round pick of the Seahawks in 2021, will miss the season.
He has appeared in 39 games, starting 13, and has totaled 74 tackles, two interceptions, an interception return for a touchdown, eight passes defensed and two forced fumbles.
The 49ers also swapped out quarterbacks Thursday, signing Tanner Mordecai and releasing Nate Sudfeld.
Mordecai originally signed Aug. 8 but spent only three days on the roster. Sudfeld spent only two days on the roster.