After going 4-12 in 2016, the Rams finished 11-5 in McVay's first season. They won a division title for the first time since 2003 and are the first team in the Super Bowl era to go from last to first in scoring in consecutive years.
McVay turns 32 next Wednesday.
Also on Thursday, the PFWA named Philadelphia Eagles executive vice president of football operations Howie Roseman as Executive of the Year and Minnesota Vikings offensive coordinator Pat Shurmur as Assistant Coach of the Year.
Shurmur is a leading candidate to become the New York Giants' head coach.
The Eagles and Vikings play each other in the NFC Championship Game on Sunday.