Mike Williams, the wide receiver, is ready to make his return to the field for the New York Jets’ season opener against the San Francisco 49ers. Williams has recovered from knee surgery last September and participated in full practice this week. He’s feeling fit and prepared to contribute to the team. Coach Robert Saleh plans to use Williams carefully, but is confident he will make a positive impact. The Jets signed Williams to a one-year, $10 million contract, hoping he’ll be a difference-maker in their offense.