Last month, head coach Kyle Shanahan expressed doubts about Jackson's participation in training camp.
"Anytime you do that type of surgery that he had ... those are big surgeries," Shanahan said. "They're tough to come back from. You never know how they're going to react. We always know it's a possibility to take a long time, and it's taking a long time."
San Francisco selected Jackson (6-4, 273) from USC with the No. 61 overall pick in the 2022 NFL Draft. Last season, Jackson recorded seven tackles, including two for a loss, three quarterback hits, three sacks, and a pass defensed before his season ended, per Pro Football Reference.
Jackson, 23, has accumulated 21 tackles, including five for a loss, nine quarterback hits, six sacks, nine passes defensed, and an interception in 23 game appearances over his two NFL seasons.
In other roster moves, according to the NFL transaction wire, the 49ers have removed wide receiver Malik Turner from injured reserve with an injury settlement. Wide receiver Terique Owens has been placed on the injured reserve list after clearing waivers.