Trainer Ronnie Shields, known to most fans primarily for his work with Mike Tyson, David Tua, Evander Holyfield, Arturo Gatti and other boxing stars, confirmed earlier speculation in an interview with ThaBoxing Voice that that Anthony Joshua's (24-2-1, 21 KOs) boxing tour of the U.S. halls aims to find a new trainer before a rematch with Oleksandr Usyk (19-0, 13 KOs) scheduled for next spring.