Robert Saleh is set to return to the San Francisco 49ers as defensive coordinator after a challenging stint as head coach of the New York Jets. With a record of 20-36 over three seasons, Saleh reflects on the experience as educational, eager to refocus on defense. His arrival signifies a potential revival of the 49ers' defensive prowess, particularly with first-round pick Mykel Williams pairing with All-Pro Nick Bosa. However, the defense faces challenges with key losses such as Dre Greenlaw and Talanoa Hufanga, suggesting a transitional phase ahead.