No. 3: Will Parks (free agent)
Luckily, San Francisco isn't seeking out full-time starters who can deliver at a Pro Bowl level. Talanoa Hufanga was a starter, but Ji'Ayir Brown replaces him. And George Odum was primarily a special teams ace.
So, in looking at players who primarily contribute on the third phase of the game, free-agent defensive back Will Parks could be an easy fit.
The 29-year-old journeyman has bounced around the league quite a bit over his career, including recent stops with the Miami Dolphins and New York Jets.
While the bulk of his field time was on special teams, working under head coach Robert Saleh's defensive system could aid in his acclimation to joining the 49ers and their own defense.
Should Parks be called upon to play defense, that is.