Via NBC Sports’ Peter King:

In December, McCarthy stayed in Green Bay, Wisconsin, with his family after getting fired and spent his days studying all things football in a “huge refurbished barn/garage/full-court basketball floor.”

According to King, McCarthy would often work with three other coaches, including former New Orleans Saints head coach Jim Haslett.

McCarthy and his staff would study everything, from reviewing “every offensive snap of the top 10 offenses last year,” to dissecting formations and play calls, to reviewing quarterback footage.

McCarthy also designed what his football operations staff would look like, with a “14-person Football Technology Department, including a six-person video unit and an eight-person analytics team.”