Sean Franklin, right, started 95 regular season matches in four seasons. (Pablo Martinez Monsivais/Associated Press)

Defender Sean Franklin, who started 95 regular season matches for D.C. United over four seasons, was among nine players who did not have their contract options exercised by the MLS club.

Franklin, who turns 33 in March, joined United through the re-entry draft before the 2014 season and was United’s first-choice right back for three years. A conversion to center back this year did not pan out and, amid injuries, he ended up starting 15 of 34 matches. The 10-year pro is eligible for MLS free agency.

United also declined options on two other natural outside backs — Chris Korb and 2017 first-round draft pick Chris Odoi-Atsem — which leaves the roster with two experienced players at the wide defensive positions: left back Taylor Kemp and right back Nick DeLeon, a former midfielder.

One source said the club will continue to evaluate Odoi-Atsem, a former DeMatha High and University of Maryland right back from Mitchellville, Md., and could bring him back. He appeared in nine league matches and started five.

United also declined options on goalkeeper Steve Clark and midfielder Lloyd Sam. However, the club and Clark, who is atop the depth chart in the wake of Bill Hamid’s move to Denmark, are “actively engaged in contract discussions and are close to an agreement on a new contract,” a source said. One source said United was uncomfortable with the terms of Clark’s option and sought to restructure the deal.

Sam, a 33-year-old winger, posted five goals and 12 assists in 43 league appearances since arriving in a trade with the New York Red Bulls during the 2016 season. He lost his full-time starting job last summer when United signed U.S. national team midfielder Paul Arriola. Like Odoi-Atsem, Sam remains on United’s radar, although he could find a new home through the league’s re-entry draft.

Others trimmed from the roster: rookie goalkeeper Eric Klenofsky; forward Deshorn Brown (two goals in 16 matches); midfielder Julian Buescher, a 2016 first-round pick who finished the season on loan to second-division Rochester; and midfielder Rob Vincent, who missed the season with chronic knee problems.

Midfielders Patrick Nyarko and Marcelo Sarvas are free agents and not expected to return. Nyarko, who turns 32 in January, started 35 times in two seasons but missed the last three months of the 2017 campaign with a concussion, his seventh in nine years. Sarvas, 36, started 45 matches in defensive midfield over two seasons.

United exercised options on six players, including Argentine central midfielder Luciano Acosta. Nine players have guaranteed contracts in 2018.

The flurry of moves leaves 15 players on the roster and up to 15 slots available this winter. Clark will presumably fill one spot, and the club will pursue another goalkeeper to compete for the starting job. United exercised its option on Travis Worra, who is expected to occupy the third-choice goalkeeping role.

Guaranteed contracts (9): Paul Arriola, Steve Birnbaum, Russell Canouse, Chris Durkin, Ian Harkes, Jared Jeffrey, Bruno Miranda, Patrick Mullins, Zoltan Stieber.

Contract options exercised (6): Luciano Acosta, Nick DeLeon, Taylor Kemp, Kofi Opare, Jalen Robinson, Travis Worra.

Contracts options not exercised (9): Deshorn Brown, Julian Buescher, Steve Clark, Sean Franklin, Eric Klenofsky, Chris Korb, Chris Odoi-Atsem, Lloyd Sam, Rob Vincent.

Retired: Chris Rolfe.

Out of contract: Bill Hamid (who signed with Danish club Midtjylland), Patrick Nyarko and Marcelo Sarvas.

Using 2017 figures, the departure of nine senior players will clear about $2.3 million from the salary cap. That group includes defender Bobby Boswell, who apparently remained on United’s books after being traded to Atlanta in August. Korb, Buescher, Odoi-Atsem and Klenofsky were exempt from the cap.

United notes: Mullins and Robinson are slated to join Swansea City for a few weeks of offseason workouts. Also, Coach Ben Olsen will travel to Wales next week to observe the Swans’ staff and watch training sessions. The common denominator is United investor Jason Levien, who owns a share of the Premier League club. … A week before the season opener, United will play a preseason friendly on the road Feb. 24 against Las Vegas Lights, a USL expansion team. The previous weekends, the new second-division side will host Montreal and Vancouver. United is in the process of finalizing preseason plans, the bulk of which will take place in Clearwater, Fla., and the Tampa-St. Petersburg area.