The specter of collusion – and the potential for resulting labor unrest – has lingered in the background during Major League Baseball’s slowest off-season in history.

And now a prominent player agent has taken that elephant in the room and given it center stage.

Brodie Van Wagenen, the lead baseball agent at Creative Artists Agency, accused MLB’s owners of conspiring to suppress the free agent market and warned that players might be willing to boycott spring training in solidarity if the market does not loosen.

Such a boycott would run afoul of federal labor laws, with the National Labor Relations Board likely issuing an immediate injunction. MLB is governed by the most recent collective bargaining agreement, ratified in December 2016 and running through 2021.

Van Wagenen wrote in a statement he tweeted Friday that behavior among owners “has changed dramatically” and that the activity “feels coordinated, rightly or wrongly.”

“Many club presidents and general managers with whom we negotiate with are frustrated with the lack of funds to sign the plethora of good players still available, raising further suspicion of institutional influence over the spending,” Van Wagenen wrote.

“Even the algorithms that have helped determine player salaries in recent years are suggesting dramatically higher values than owners are willing to spend.”

A backlog of impact players remain on the market with just 10 days remaining until spring training camps open. Seven of the consensus top 10 free agents, led by J.D. Martinez, Yu Darvish and Jake Arrieta, remain unsigned, and productive players such as Van Wagenen’s client, former New York Yankees third baseman Todd Frazier, remain days and perhaps weeks away from finding their place in this market.

More than 120 free agents remain unsigned.

The MLB Players Association issued a statement later in the day by executive director Tony Clark, which called free agency the "cornerstone of baseball's economic system" and said, "Each time it has been attacked, Players, their representatives and the Association have united to defend it."

Van Wagenen, who has negotiated nine-figure contracts for the likes of Ryan Howard, Robinson Cano and Ryan Zimmerman, says players are ready to flex their collective will in a fashion not seen since the last player strike began in 1994.

“(Players) are outraged,” he wrote. “Players in the midst of long-term contracts are as frustrated as those still seeking employment. Their voices are getting louder and they are uniting in a way not seen since 1994.

“I would suggest that testing the will of 1,200 alpha males at the pinnacle of their profession is not a good strategy for 30 men (owners) who are bound by a much smaller fraternity.

“A fight is brewing. And it may begin with one, maybe two, and perhaps 1,200 willing to follow. A boycott of spring training may be a starting point if behavior does not start to change.”

MLB commissioner Rob Manfred said at Thursday’s owners’ meetings that a myriad of factors conspired to slow a market in which outfielder Lorenzo Cain (five years, $80 million) has signed the largest contract to date.

“Every [free-agent] market is different,’’ Manfred said. “There's different players, different quality of players, different GMs, different decisions, a new basic agreement, different agents who had particular prominence in a particular market in terms of who they represent.

“Those factors, and probably others that I can't tick off the top of my head, have combined to produce a particular market this year. Just like there's been some markets where the lid got blown off in terms of player salary growth, occasionally you're going to have some that are not quite as robust.’’

Baseball has not had a work stoppage since 1994-95, when owners’ threats of a salary cap caused players to walk out in August 1994. Labor peace has reigned since, but a luxury tax phased in since the last stoppage has in recent years served as a de facto cap for some teams.

While rhetoric has been minimal this winter, it is starting to ramp up. Los Angeles Dodgers closer Kenley Jansen said at his team's fan fest last weekend that players might want to consider striking. Super agent Scott Boras told USA TODAY Sports on Monday that a "non-competitive cancer" was ruining the game.

The full text of Van Wagenen's statement:

Contributing: Bob Nightengale