SANTA CLARA, Calif. -- Here are five moves the San Francisco 49ers should consider when free agency opens at 4 p.m. ET Wednesday:

Priority No. 1 -- Re-sign NT Ian Williams: Showing what he can do when fully healthy, Williams was a fixture, if not a force, in the trenches for the 49ers last year. Playing in 16 games for the first time in his career, he had a career-high 65 tackles with a sack. He was respected enough to be voted a team captain last year and the rebuilding 49ers need continuity.

Chiefs cornerback Sean Smith would add veteran leadership to the 49ers' secondary and immediately improve the unit. Kirby Lee/USA TODAY Sports

Priority No. 2 -- Sign CB Sean Smith: A big cornerback at 6-foot-2, 215 pounds, Smith was a No. 1 cornerback for the Kansas City Chiefs and while the 49ers do have a cadre of talented young corners, Smith would offer an immediate upgrade in the secondary. Especially because Tramaine Brock, who operates better as a No. 2 corner, could move back to his strength.

Priority No. 3 -- Sign LB James Laurinaitis: Another page from the strengthen-yourself-while-weakening-a-divisional-foe handbook, Laurinaitis, recently cut by the Rams, would be an immediate upgrade inside the 49ers' 3-4 defense, next to All-Pro NaVorro Bowman. Laurinaitis has yet to miss a game in seven seasons, starting all 112. With 10 career interceptions and 16.5 career sacks, Laurinaitis has more than Bowman, three and 11.5, respectively, though Bowman has played in two fewer seasons.

Priority No. 4 -- Sign G Kelechi Osemele: If the 49ers let Alex Boone walk, which is probably a fine idea given his mercurial history with the team, the powerful Osemele might be an even better fit. Osemele, a second-round pick of the Baltimore Ravens in 2012, has played all over the offensive line, but for the 49ers projects as a left guard ... which is where Boone played last year.

Priority No. 5 -- Sign WR Marvin Jones: With Anquan Boldin likely gone, the 49ers need that big possession receiver to run the underneath and intermediate routes in new coach Chip Kelly's system. Riley Cooper is also intriguing, given his history with Kelly, as is Mohamed Sanu, Jones' Cincinnati Bengals teammate. Neither Jones, Sanu nor Cooper has a 1,000-yard receiving season, while Boldin has seven.