Paulo Andre said the more than 1,000 players who belong to the Common Sense FC union realise it will be tough to alter the 2014 calendar because the season is broken up by the World Cup, which will be held in Brazil for the first time since 1950.
But they are only prepared to suffer through next year's arduous schedule ifs the Brazilian Football Confederation plans widespread changes for 2015. If that does not happen, they will take action.
"We are looking to discuss this and will do so right to the end but when there's no more chance of negotiations then a strike becomes a plausible option," Paulo Andre said on Brazil's TV Cultura.
"We accept sacrifices will have to be made in 2014 as long as there are changes in 2015," he added. "If that doesn't happen then 2014 might not start. The players are united and we are strong and we're prepared to take action."
Brazil's state championships are due to begin in mid-January, just over a month after the national league ends.
The players, including dozens of current and former Brazil internationals want a shorter season; a 30-day close season holiday; an extended pre-season; financial fair play rules; and more representatives on decision-making bodies such as clubs and federations.
They argue that the top Brazilian clubs play, on average, 20 matches more than their European counterparts and do not enjoy a month-long pre-season, a factor that contributes to injuries.
They also want teams who do not pay their players on time - a regular occurrence in Brazil - to be docked points.
The union, which was formed in September, has launched increasingly eye-catching protests in recent weeks.
At first, teams linked arms in solidarity before kickoff while last week they stopped games for up to a minute. More action is expected before the season ends on Dec. 8.