The A's current stadium is run down. A sewage problem forced the A's and Seattle Mariners to use the same locker room after Sunday's game.
The pipes backed up on the lower levels of the stadium, creating a stink and pools of water in the clubhouses used by both teams and the umpires.
Gregory said Wolff is not involved in the lawsuit.
Baseball's antitrust exemption was granted by the U.S. Supreme Court in 1922, with the court ruling that baseball is not interstate commerce.
While baseball may have started as a local affair, it is "squarely in the realm of interstate commerce," the lawsuit contends.
"MLB clubs ply their wares nationwide, games are broadcast throughout the country on satellite TV and radio, as well as cable channels and MLB clubs have fan bases that span from coast to coast," the lawsuit says.
Associated Press Writer Mihir Zaveri contributed to this report.