Major League Soccer and its players' union have agreed in principle to a five-year labour contract, a person familiar with the deal told The Associated Press, averting a possible strike ahead of Friday's season opener.

The person spoke on condition of anonymity Wednesday because the agreement had not been announced. The deal, the culmination of talks that began last weekend, was likely to be announced later Wednesday night and would replace the contract that expired Jan. 31.

MLS's 20th season begins this weekend, with the defending champion Los Angeles Galaxy hosting Chicago in the opener. The Fire travelled to California on Wednesday for the match.

Orlando and former FIFA Player of the Year Kaka host New York City and former Spanish World Cup champion David Villa on Sunday in the debut of the two expansion teams that raise the league's total to 20.

The league and the U.S. Soccer Federation are in the first year of eight-year broadcast agreements with ESPN, Fox and Univision Deportes.

Players were seeking free agency from MLS, which was set up as a single entity in which the league owns all players' contracts. While stars such as Seattle's Clint Dempsey earn up to nearly $7 million, half the league's players last September had salaries under $100,000, according to the union.

The players' union was seeking a rise in the minimum salary, which generally was $48,500 last year but contained a provision in which some players could be paid as low as $36,500.

The previous labour deal, in 2010, was reached five days before the season opener.