Fifteen years after starting his professional MMA career, and six years after becoming the UFC welterweight champion in one of the greatest upsets of all time, veteran fighter Matt Serra has told Newsday that he is “walking away” from the sport after a life-threatening health scare.   I really think I’m walking away, Serra said. I’m going to be 39, I just had my rib taken out. I’m having my third kid. My schools are doing well. What am I doing, looking for another pay day? It’s not really for that. I mean, it doesn’t stink, but it’s not really for that. Am I still trying to hold on for the glory? Glory is a drug, dude. I’m telling you, that’s the problem. It really is. I know why guys can’t walk away. I absolutely get it. Serra developed three blood clots that hospitalized him ”” two in an arm and one more in a lung. Then I got freaked out, the Long Island native said. You don’t catch that [and] after the lung, that stops your heart or your brain. Then you’re done. I’m very fortunate to, basically, be here. Sounds kind of morbid. If I didn’t catch that ”” I was about to go to bed. I’m like, man, something’s not feeling right. Serra now takes blood thinners and has to receive injections of an anticoagulant per day for the next three months. The blood clots in his arm caused another serious health condition, which required surgery. According to Newsday, Serra’s collarbone and first rib on his left side were compressing a blood vessel and restricting blood flow ”” a condition known as thoracic outlet syndrome ”” which forced him to have the rib removed in early May. Despite not having fought since 2010 and now dealing with these serious health issues, Serra cannot bring himself to shut the door completely on fighting in the future or even to use the word retirement.