The union representing MLS referees claimed this week that a management representative threatened retribution against its members, prompting a second unfair labor practice charge as the sides work toward a collective bargaining agreement.

The latest complaint filed with the National Labor Relations Board says an individual from the Professional Referee Organization, which manages officiating programs in U.S. leagues, “threatened multiple members with discipline and additional unlawful threats of reprisals if those members continued to support the union.”

The incident occurred around Feb. 1 at the referees’ preseason training camp in the Orlando area, the grievance said. Steve Taylor, lead negotiator for the Professional Soccer Referees Association, said at least 10 members were approached. “Some were told flat-out that they would never work in MLS again,” Taylor said.

PRO General Manager Peter Walton said he was “not aware of any incidents of such a nature” and would await specifics from the PSRA before commenting further.

Said Taylor: “It’s frustrating to say the least when real progress is being made on both economic and non-economic issues at the table, only to hear yet another disturbing account of ongoing unfair labor practices being taken against our members by the employer. The membership is upset, and rightly so. While they’re working hard to focus and prepare for the upcoming season, the employer seems more interested in trying to strong-arm them into not participating in the normal and federally protected activities of their labor union.”

Two weeks ago, PSRA filed a charge with the NLRB saying PRO failed to respond to several information requests; engaged in “regressive bargaining by withdrawing a number of tentative agreements without good cause;” failed to “bargain in good faith;” and was not available for meetings.

Walton last week refuted those claims.

There is no timetable for the NLRB to respond to the complaints, although it would probably address the most recent one first because of the serious nature.

PSRA and PRO are scheduled to meet in Washington next week and New York the following week.

It remains unclear how the union will respond if a CBA is not reached before the season begins March 8.

“We remain cautiously optimistic,” Taylor said of the negotiations. “Our officials are ready to work and we’re all looking forward to the start of the season.”

PRO employs 20 full- and part-time match officials and an additional 56 who are compensated on a per-game basis. These 76 officials comprise the entire pool of people eligible to work matches as referees, assistant referees and fourth officials in MLS.

MLS is PRO’s primary financial backer, with the USSF contributing a smaller share.