CHARLOTTE, N.C.—Superman has returned. Whether or not Cam Newton can rescue the Carolina Panthers’ sinking season remains to be seen. The Panthers (4–5) announced they’ve signed Newton to a one-year contract, bringing him back to the franchise that drafted him No. 1 overall in 2011—and later cut him prior to the 2020 season after he lost eight straight games as a starter. The deal is worth $10 million, including $4.5 million in fully guaranteed money and a $1.5 million roster bonus, according to a person familiar with the situation. The person spoke to The Associated Press on condition of anonymity because the team does not announce financial terms of players’ contracts. “A healthy Cam Newton is a special player,” Panthers coach Matt Rhule said. Carolina was in need of a quarterback after an MRI on Monday revealed starter Sam Darnold would miss at least four weeks with a incomplete fracture …