After playing four seasons in the NFL, former Cowboys defensive lineman David Irving officially decided to call it quits this month. 

The decision by Irving came less than a week after he had been hit with an indefinite suspension by the NFL for violating the league's substance abuse policy. The suspension for Irving was the third one of his career following suspensions in both 2017 and 2018 that each lasted four games. 

All three suspensions were related to marijuana, and apparently, Irving's decision to keep smoking pot seriously damaged his relationship with Cowboys coach Jason Garrett. During a recent interview with USA Today, Irving claims that Garrett told him to quit football so that he could smoke more weed. 

"He told me I should just quit, smoke all the weed I want, the team didn't need me," Irving said. "I'm a distraction to the team."

Irving says he's been diagnosed with multiple mental illnesses -- including manic depression, borderline schizophrenia, post-traumatic stress disorder and bipolar disorder -- that all came from the concussions he suffered while playing football. According to Irving, he smokes pot to help ease his pain. 

"You can check all my medical records. I wasn't diagnosed with any of these things before the NFL," Irving said. "I've been in what, four and a half years now? It was scary to know I played a sport and am having these concussions and I don't really know how long I'm going to live. Memory loss, pains, [and] I have these mood swings, bipolar disorder. If you ask me, it's all related to the concussions."

Irving's choice to medicate himself with marijuana ended up being a divisive issue between him and Garrett. 

"He views marijuana as a drug, whereas I view it as a medicine. It's not a good situation," Irving said. 

The 25-year-old claims that Jerry Jones understood his situation, but there was nothing the Cowboys owner could do to help. 

"Basically, Jerry, he is supportive of me," Irving said. "He understands my situation and what I was dealing with. Our hands were pretty much tied. His hands were tied."

Now that he's retired, Irving will continue to smoke pot, but he made it clear that pot isn't the reason why he quit football.  

"I didn't quit football to smoke weed," Irving said. "That would be idiotic. I understand that. . . . It's about wellness, about rights. People need to understand that."

When Irving officially announced his retirement on March 7, he used an Instagram video to basically take a shot at the NFL's draconian policies against marijuana. 

"We got this opioid thing going on and I'm prescribed all that bulls---, and I just think it's bulls--- that we've got to deal with that policy," Irving said. "Everyone thinks it's about smoking weed. It's not about smoking weed. It's much bigger than that. Much, much bigger. Hell, I have concussions every day. I get to see around the office how that f---s your head up and I feel it."

In the video, part of which you can see below, Irving even appeared to be smoking pot. 

The former undrafted free agent will end his career with 12.5 sacks during his four seasons with the Cowboys. If the NFL ever does change its marijuana policy, it likely wouldn't come until the league hammers out a new collective bargaining agreement with the NFLPA. The current CBA is set to expire after the 2020 season, which means a new one could be in place for the start of the 2021 season.