With the Dallas Cowboys star suspended indefinitely after once again violating the league's substance abuse policy, Carter talked about the effort he's made to help Gregory over the years.

"It's unfortunate for him," Carter said on FS1's "First Things First" ... "He's one of a number of guys through the years I've tried to help."

"[I've] tried to give him the power through rehab, through the system of [Alcoholics Anonymous], through going to meetings. The system has worked for me for almost 30 years."

Carter has had his own struggles with substance abuse -- he's openly talked about it -- and feels programs like AA have had a huge impact on his life.

As for Gregory, Carter says he's even gone to bat for the defensive end with NFL officials -- writing a letter to the front office in an effort to get him reinstated after a previous substance abuse violation.

"He's struggled like a lot of other talented players have struggled with the disease," Carter said.

"I wish people would look at [addiction] like cancer and if your cancer came back what would you do?"

"Randy Gregory, call me, man. Anybody out there, call me ... because I still got feelings for you."

26-year-old Gregory was a BEAST for the Cowboys in 2018 -- logging 6 sacks and 28 QB pressures.