CHARLOTTE, N.C. (AP) — A person familiar with the situation says the Panthers have agreed to terms on a two-year contract with former XFL quarterback P.J. Walker of the Houston Roughnecks. The move prompted Carolina to trade quaraterback Kyle Allen to the Washington Redskins, where Allen will be reunited with former coach Ron Rivera. The Panthers also announced the previously reported signings of three unrestricted free agents — linebacker Tahir Whitehead from the Raiders, defensive end Stephen Weatherly from the Vikings and offensive lineman John Miller from the Bengals.