The biggest concern surrounding the San Francisco 49ers' reunion with Robert Saleh is the possibility of him becoming the team's third consecutive one-and-done defensive coordinator.

Saleh, who was fired in October as the New York Jets head coach five games into his fourth season, generated interest on the head-coaching front and was seen as one of the frontrunners for the Jacksonville Jaguars job. He also interviewed with the Las Vegas Raiders and Dallas Cowboys.

Robert Saleh cannot personally create turnovers, rush the passer or stop the run. His return as the 49ers’ D-coordinator is no guarantee of success.