San Francisco is expected to hold a rookie minicamp at the end of next week.
Brewer (6-4, 230) played five seasons for the Longhorns, hauling in 59 passes for 611 yards with eight touchdowns during his collegiate career. He had a career-best 22 catches for 184 yards and three scores in his final season with Texas, earning All-Big 12 honorable mention.
In his one game with the Kats, Brewer hauled in a team-high three catches for 58 yards, a long of 31 yards, and averaged 19.3 yards per catch.
"This is exactly what we want for our Kats players," Kats coach Dean Cokinos said. "Sure, we will miss Cade as a person and a player. But through our evaluation processes for all our players, we want to identify players with a high ceiling who are also engaged in our community."
In 2022, Brewer got a shot with the Seattle Seahawks, signing with the team after going undrafted. He caught three passes for 17 yards in two preseason games with Seattle.