The victims have been named as Gavin Escobar, 31, and Chelsea Walsh, 33, both of Huntington Beach, California, by the Riverside County sheriff's coroner's office.
From 2013 through 2016, Escobar was a tight end with the Dallas Cowboys. He has 30 catches and eight touchdowns in his career while being listed at 6-foot-5 and 247 pounds.
A climbing mishap involving two wounded persons was reported at Tahquitz Rock in the San Bernardino National Forest on Wednesday about noon local time, according to Cal Fire.
The victims' deaths were said to have occurred as they were scaling a "rock face," but no additional information was supplied. It was unclear if they were seasoned climbers or novices.
Escobar attended San Diego State University after graduating from Rancho Margarita High School.
The Cowboys selected him in the second round of the 2013 NFL Draft. Escobar left football to work as a firefighter in Long Beach.