Like every offseason, the San Francisco 49ers roster will undergo a certain amount of turnover in the coming months. That's par for the course in the NFL.

This year, the 49ers have 11 free agents, including six who are unrestricted. For all the key dates in free agency to be aware of, read and bookmark this post. Also, here are brief explanations of what it means to be an unrestricted, restricted and exclusive rights free agent.

Now let's get to a primer on San Francisco's players who could hit the open market come March 9. Names are listed in alphabetical order.

LB RAY-RAY ARMSTRONG

Season: 24 tackles, one sack in 15 games (five with 49ers)

Career: 57 tackles, one sack, one forced fumble, two fumble recoveries in three seasons

Status: Restricted free agent

Notes: The Oakland Raiders waived Armstrong on Nov. 24 before the 49ers claimed him a day later. The linebacker went undrafted in 2013 out of Miami but still played 16 games as a rookie for the St. Louis Rams. He has started five games in his career, including two this year for Oakland. He saw limited playing time in San Francisco, with most of his snaps coming on special teams.

WR ANQUAN BOLDIN

Season: 69 catches, 789 yards, four touchdowns in 14 games

Career: 1,009 catches, 13,195 yards, 74 touchdowns in 13 seasons

Status: Unrestricted free agent

Notes: Acquired in a March 2013 trade with the Baltimore Ravens, Boldin has been San Francisco's leading receiver in each of the last three seasons. In 2015, Boldin surpassed the 13,000-yard and 1,000-catch marks for his career. He is a three-time Pro Bowler and a two-time finalist for the Walter Payton NFL Man of the Year Award. He turns 36 years old on Oct. 3 but has said he wants to play again in 2016.

G/T ALEX BOONE

Season: Played 13 games, all starts, at left guard

Career: Played 77 games, including 59 starts, at guard and tackle in six seasons

Status: Unrestricted free agent

Notes: The 49ers signed Boone as an undrafted free agent out of Ohio State in 2009. He is a two-time Pro Bowl alternate (2013, 2015). He started 46 games for San Francisco at right guard from 2012-14 before moving over to left guard this season. He started the first 13 games of 2015 before a knee injury ended his year early.

RB REGGIE BUSH

Season: Eight carries for 28 yards, four catches for 19 yards in five games

Career: 1,274 carries for 5,493 yards and 35 touchdowns, 470 receptions for 3,508 yards and 18 touchdowns in 10 seasons

Status: Unrestricted free agent

Notes: Signed as a free agent last offseason, Bush was hampered by injuries all year. After a calf strain slowed him down in the early goings of the season, the running back suffered a severe knee injury when he slipped on the concrete track at the Edward Jones Dome in Week 8. The 30-year-old is the active leader for receptions by a running back (470).

TE GARRETT CELEK

Season: 19 catches, 186 yards, three touchdowns in 11 games

Career: 27 catches, 328 yards, three touchdowns in four seasons

Status: Unrestricted free agent

Notes: The 49ers signed Celek as an undrafted free agent out of Michigan State in 2012. This year, despite San Francisco beginning training camp with eight tight ends, Celek broke out and delivered a career season across the board. His best game came in a Week 9 victory versus the Atlanta Falcons, when he caught two touchdown passes from Blaine Gabbert. San Francisco placed Celek on the Injured Reserve List on Dec. 8 with a high ankle sprain.

K PHIL DAWSON

Season: 24-for-27 on field-goal attempts with long of 54 yards, 20-for-21 on point-after attempts in 16 games

Career: 386-for-457 on field-goal attempts with long of 56 yards, 447-for-456 on point-after attempts in 17 seasons

Status: Unrestricted free agent

Notes: The 49ers signed Dawson as a free agent in 2013 after he spent the first 14 years of his career with the Cleveland Browns. Of his three missed field goals this year, only one wasn't blocked. He made the Pro Bowl in 2012 and is a two-time All-Pro (2007, 2012). He was voted as the 49ers team MVP in 2015. The 41-year-old told reporters at the end of the season that he wants to return for 2016.

OL JORDAN DEVEY

Season: Played 15 games, including nine starts, at right guard

Career: Played 22 games, including 13 starts, at guard in two seasons

Status: Exclusive rights free agent

Notes: Devey came to the 49ers in an August trade with the New England Patriots in exchange for tight end Asante Cleveland. He entered the league in 2013 as an undrafted free agent out of Memphis. He began the 2015 campaign as the starting right guard and ended it mostly as a reserve lineman.

RB SHAUN DRAUGHN

Season: 78 carries for 273 yards and one touchdown, 27 receptions for 176 yards in 11 games (six with 49ers)

Career: 151 carries for 527 yards and three touchdowns, 51 receptions for 334 yards in four seasons

Status: Restricted free agent

Notes: Draughn signed with the 49ers on Nov. 2 after Pierre Garçon went down with a foot injury that required surgery. San Francisco was Draughn's eighth team in five years since entering the NFL as an undrafted free agent out of North Carolina in 2011. He started all six games that he appeared in for San Francisco in 2015. He totaled 77 yards from scrimmage or more in four straight games from Week 9 to Week 13. A knee injury versus the Cincinnati Bengals on Dec. 20 prematurely ended his season.

DT TONY JEROD-EDDIE

Season: 14 tackles, four pass deflections in 16 games

Career: 62 tackles, six pass deflections, one fumble recovery, one interception in four seasons

Status: Restricted free agent

Notes: Jerod-Eddie signed with the 49ers as an undrafted free agent out of Texas A&M in 2012. The 25-year-old has appeared in all but one game for San Francisco since 2013. He has served as depth along the team's defensive line throughout his career.

LB MICHAEL WILHOITE

Season: 85 tackles, one interception, one pass deflection in 12 games

Career: 213 tackles, eight pass deflections, three interceptions, one forced fumble in four seasons

Status: Restricted free agent

Notes: After going undrafted in 2011 out of Washburn, Wilhoite initially signed with the Omaha Nighthawks of the UFL. The 49ers scooped him up in December of that year and signed him to the practice squad. In 2014, Wilhoite started all 16 games with NaVorro Bowman injured. This year, after Patrick Willis retired, Wilhoite started the first 12 games before an ankle injury sidelined him for the final four weeks.

NT IAN WILLIAMS

Season: 65 tackles, one sack, one forced fumble, one fumble recovery, one pass deflection, one blocked kick in 16 games

Career: 91 tackles, two sacks, two pass deflections, one forced fumble, one fumble recovery, one blocked kick in four seasons

Status: Unrestricted free agent

Notes: Another undrafted free agent, Williams signed with the 49ers out of Notre Dame in 2011. Injuries limited Williams to just 10 games from 2013-14. He stayed healthy this year, starting all 16 games for San Francisco at nose tackle. He was named a team captain in 2015.