First in a series upcoming the Raiders and NFL free agency, which begins March 7:

For all the good things Raiders general manager Reggie McKenzie has done in procuring talent over the past two seasons, identifying cornerbacks and safeties has been a problem area since he arrived in 2012.

Other than bringing in Charles Woodson, who had three good seasons to close out a Hall of Fame career, McKenzie has mostly swung and missed.

For three years, the Raiders looked to past-their-prime players to be starting cornerbacks, and they were predictably either injured or didn’t have enough left in the tank _ Ron Bartell and Shawntae Spencer in 2012, Mike Jenkins and Tracy Porter in 2013 and Tarell Brown and Carlos Rogers in 2014.

The draft brought a decent value in returning player TJ Carrie (seventh round, 2014) as a well as a potential bust (DJ Hayden, first round, 2013) while the picks of Keith McGill (fourth round, 2014) and Dexter McDonald (seventh round, 2015) remain an open question.

McKenzie and coach Jack Del Rio will give it another shot in 2016. The Raiders will need at least two new starters and possibly three. Waiver claim David Amerson, assuming he doesn’t revert to his 2014 form with Washington, should start, and Carrie could factor at either the other cornerback spot or safety.

Ideally, they Raiders will sign both a safety and a corner in free agency and then add each position in the draft as well.

The Raiders have an estimated cap space of more than $74 million, meaning they can afford anyone they want. Still, even with that much room to operate, McKenzie isn’t likely to go much over his own idea of a player’s worth. That’s the way he rolls.

A look at some free agent possibilities when free agency begins March 9, as well as returning players and their own free agents:

UNRESTRICTED FREE AGENTS

Cornerbacks

Sean Smith, Kansas City: The Chiefs franchised safety Eric Berry, which could leave Smith on the market for a big-money deal. Smith is in his prime at 28, has the size the Raiders love (6-3, 218) and Del Rio is fond of raiding division rivals (see Rodney Hudson last year).

Janoris Jenkins, Los Angeles: Jenkins (5-10, 198) was a candidate to franchised but lost out to fellow corner Trumaine Johnson. He has a knack for scoring touchdowns _ five in his career. One negative _ according to Profootballfocus.com, Jenkins has five touchdown passes in each of the last three seasons.

Casey Hayward, Green Bay: Hayward had three pretty solid seasons for the Packers, and has experience both in the slot and outside. McKenzie will always give a close look to former Packers. He will turn 27 in September.

Prince Amukamara, N.Y. Giants: Someone will sign the former first-round pick out of Nebraska. But Amukamara has missed way too much action because of injuries, playing a full 16-game schedule only once in 2013.

Safeties

Eric Weddle, San Diego: A hard-nosed player the Raiders have admired from the other side of the line of scrimmage, Weddle is 31 years old and may have too much wear and tear for McKenzie’s liking. But as Woodson showed, smart players can compensate with know-how at safety in a way they can’t at cornerback.

Reggie Nelson, Cincinnati: The best pure centerfielder in the free agent market, Nelson had a career-high eight interceptions for 115 yards in returns. One potential problem _ Nelson was a first-round pick with Jacksonville when Del Rio was coach, got himself in the doghouse after a strong rookie season and wound up being dealt for a conditional draft pick. The other issue? He’s 32 years old.

Rodney McLeod, Los Angeles: Has started 48 games for the Rams over the past three seasons and is only 25 years old. Has only five career interceptions but has the reputation of being a hard hitter with seven forced fumbles. Profootballfocus.com graded McLeod out higher than either Jenkins or Norris, the Rams starting corners.

George Iloka, Cincinnati: Classic strong safety size at 6-4, 225 but has also played in the deep middle even with Nelson around. Has shown the ability to defend against the league’s toughest tight ends. Iloka was limited to 12 games because of injury.

Walter Thurmond, Philadelphia: Has the Ken Norton factor going for him, having signed a one-year deal in Philadelphia after playing for Seattle from 2010 through 2013. Thurmond made the transition from corner to free safety last year, and the Raiders love that kind of versatility. Lots of problems with injuries until he played 16 games last season.

Tashaun Gipson, Cleveland: Coming off a poor season on a bad Browns defense, but Gipson had a high coverage grade in 2014 for Profootballfocus.com as well as six interceptions. Could be had at a nice price, and McKenzie loves the idea of a bargain.

PLAYERS UNDER CONTRACT

CB David Amerson: Hard to imagine where Raiders would have been without him. Waiver claim of the year.

CB-S TJ Carrie: Remains to be seen where the Raiders believe he will settle in. Has played 28 of 32 games, but there is concern over how often he is less than 100 percent physically.

CB DJ Hayden: Time is running out. Odds are he’ll never look like the 12th pick in the draft, but becoming a serviceable player is not out of the question.

CB Keith McGill: Injuries have limited his practice time and development. The Raiders like his classic corner build (6-3, 210) but hasn’t been able to break through at a position in need of fresh talent.

CB Dexter McDonald: Played in only six games as a rookie. Will be watched closely to see if he’s a viable NFL player in Year 2.

CB SaQwan Edwards: A late-season roster addition after Nate Allen went on injured reserve, Edwards didn’t make it out of training camp a year ago.

S Nate Allen: A big-ticket free agent a year ago, Allen spent much of the season on injured reserve/designated for return and didn’t play well when he came back. Renegotiated his contract to remain at a lower price.

S Dewey McDonald: An addition to practice squad who was promoted to 53-man roster when Marcel Reece was suspended.

UNRESTRICTED FREE AGENTS

S Taylor Mays: A physical specimen who was once a second-round pick by the 49ers, Mays played in 14 games with five starts and had a career high five passes defensed.

S Larry Asante: Played in 16 games with two starts, plus played on special teams. Could be kept around for depth. Always in top condition.

RESTRICTED FREE AGENTS

CB Neiko Thorpe: Has shown enough to play in 28 games over the past two years on special teams and occasionally at cornerback (two starts in 2015) but unlikely to be counted on as a regular rotational player.

EXCLUSIVE RIGHTS FREE AGENTS

S Tevin McDonald: The son of former 49ers safety Tim McDonald bounced between the practice squad and the 53-man roster last season.