In the past two seasons, he has had 569 pass attempts, 25 touchdown passes, seven interceptions and a 93.7 passer rating. Washington’s Kirk Cousins, his possible replacement next year, has 25 TDs, 11 INTs and a 98.0 rating in his past 569 attempts. Will NaVorro Bowman, an erstwhile first-team All-Pro, become a second-string linebacker? Both head coach Kyle Shanahan and general manager John Lynch have stated Bowman, who has had two major leg injuries since January 2014, will have to fight to keep his starting spot. After receiving a contract extension in December from the old regime, tight end Vance McDonald, above, could receive a pink slip from the new guard. Several underwhelming draft picks from the Trent Baalke era have tenuous job security entering training camp. The 49ers have retained 27 of the 31 Baalke picks that Lynch inherited, but defensive tackleTank Carradine, linebacker Eli Harold and wide receiver Bruce Ellington are among the notable past selections on the roster bubble. The poster boy for the group is McDonald, a 2013 second-round pick whom the 49ers attempted to trade during the draft. Shanahan and running backs coach Bobby Turner lobbied hard for Williams, who was kicked off the team at Connecticut, briefly left the team at Utah, and eventually convinced Lynch to place him on the 49ers’ draft board and trade up for him in the fourth round. For starters, defensive tackle Solomon Thomas, above, has to sign his contract: Despite his missed time, Thomas, the 49ers’ highest selection since Alex Smith went No.