FIFA announced on Thursday that World Cup qualification games in CONMEBOL would go ahead in October as planned.
Europe-based players from South American countries must be made available for selection to their respective national teams, according to the CONMEBOL statement, with the first round World Cup qualification games set to take place on Oct. 8 and 13.
"FIFA president Gianni Infantino assured the member associations of Conmebol that the rule regarding the release of playing will not have any exceptions and South America(n) (teams) will be able to use athletes who play in foreign leagues," read the statement, which added that a health and safety protocol will be released next week.
The announcement could set up a showdown between CONMEBOL and FIFA with Europe's top clubs, who could be reluctant to let their top players travel to South America in the midst of the ongoing pandemic.
The verdict raises the prospect of Barcelona's Lionel Messi traveling to meet up with Argentina for games at home (against Ecuador) and in Bolivia, as well as Paris Saint-Germain's Neymar joining Brazil for matches against Bolivia and Peru.
CONMEBOL World Cup qualifying is a straight home-and-away league format with each nation playing each other twice and the top four advancing to the 2022 Qatar World Cup, with the fifth-place finisher entering an inter-confederation playoff.
CONCACAF had announced a new format for its qualifying last July. It included a first round involving the 30 teams ranked outside the top five in the region and a final "octagonal" phase starting next June with eight teams battling it out in a round robin format, with three places in Qatar (plus a inter-confederation playoff for fourth) at stake.
But that schedule was complicated by the cancelation of the October and November international windows, leaving the confederation scrambling to fit in the remaining dates and the possibility of the final stage of qualifying -- in which the United States, Mexico, Costa Rica, Honduras and Jamaica would enter -- not beginning until next June at the earliest.
CONCACAF teams could theoretically have to play up to 18 matches to reach the 2022 World Cup.
FIFA also announced a new window for international matches in January 2022 as World Cup qualifying fixtures continue to pile up because of the COVID-19 pandemic.
World football's ruling body said in a statement that the window was ratified by the decision-making FIFA Council on Thursday.
It applies to all continents apart from Europe, will last from Jan. 24 to Feb. 1, 2022, and means European clubs will be obliged to release their players during that period.
FIFA has also agreed that the CONCACAF Gold Cup will take place from July 10 to Aug. 1 next year and that the Africa Cup of Nations -- postponed from 2021 -- will be played in January 2022.
Apart from this month's UEFA Nations League matches, international football has been on hold since March because of the pandemic, causing widespread disruption to the qualifiers for the 2022 World Cup in Qatar.
Six match days have also been postponed in the Asian qualifiers.
Information from Reuters was used in this story.