Democratic Senate candidate John Fetterman of Pennsylvania will participate in just one debate, his campaign said Wednesday, after weeks of his Republican rival, Dr. Mehmet Oz, pressuring Fetterman and aggressively questioning the severity of his lingering health problems from a stroke. Fetterman’s campaign said he will participate in a televised debate in mid- to late October. The campaign gave no other details, including why he would agree to just one debate. Oz’s campaign immediately dubbed it a “secret debate,” with no details on when or where. Fetterman, the state’s lieutenant governor, and Oz are vying to replace retiring Republican Sen. Pat Toomey in a race Democrats see as one of their best chances nationally to flip a Republican-held seat.