Sorry, but I do not remember Ruiz being "unable to grasp the offensive calls" at center or not grasping "the concepts and reads at Center". That was his strength at Michigan. Where did you get that information? Ruiz never got the opportunity to handle center last season at all.

Saints 2020 Year-in-Review: Cesar Ruiz

"Coaches planned on McCoy, predominantly a guard in college at Texas A&M, and Ruiz to each have reps at guard and center during preseason games to find their best fits. Unfortunately, a nationwide outbreak of COVID-19 forced the cancelation of offseason workouts, preseason games, and limited training camp.

Coaches felt that leaving McCoy at center would provide the best continuity during a limited offseason. That left Ruiz to learn a new position at the NFL level with fewer reps."