But the 28-year-old Regina middleweight takes it up a level Friday night when he makes his Maximum Fighting Championship debut against Jared McComb (4-1) at "MFC 33: Collision Course" in Edmonton.
Adding to Parker's unusual journey to cage-fighting, he made it to the MFC after reaching out to owner Mark Pavelich via Facebook.
"I always enjoyed fighting. Now I've really found my sport," Parker (1-0) told The Canadian Press. "As a hockey player, that was my role.
"There's a lot of hockey players that get forced into that role whereas, for myself, I look back at it and it was just kind of the role I always wanted."
Originally from Melville, Sask., Parker played for the Lethbridge Hurricanes and Moose Jaw Warriors in the WHL before a 54-game stint in 2004-05 with the Wichita Thunder of the Central Hockey League that saw him collect six goals, eight assists and 503 penalty minutes.
According to hockeyfights.com, he had 44 fights that season including seven against Topeka's Tyler Hanchuk.
"We played them often," Parker reminisced. "He was a tough guy for sure."
He spent the better part of the next five seasons in the fight-filled LNAH (Ligue Nord-Americaine de Hockey) in Quebec, dropping the gloves for St-Hyacinthe, Sorel-Tracy and Trois Rivieres. His first season in the league, he had 70 fights and 508 penalty minutes.
"When I got there I was 22 years old and I was like a kid in a candy shop, because every team had three or four guys that were willing to fight. Like I said, I always liked fighting and I was ready to fight anybody.
"I had a lot of opportunities there."
He finished his hockey career in 2009-10 with short stops with the Flint Generals and Dayton Gems of the IHL after spending some time in the Chicago Wolves' AHL training camp.
Hockeyfights.com lists Parker as having 290 career fights. His own estimate is 350, with "probably 340" wins.
Parker recalls his father's words. "He said 'You fight, you better win."
Still he acknowledges he "had to earn some lessons along the way." That includes being knocked out.
"At the beginning in 2005-2006, yes, he was a good fighter. ... But a few years later after some KOs he was not the same," said an LNAH official.
While Parker never grew tired of his role as an enforcer, he admits it took a toll on his hands. Sometimes winning became just painful as losing.
In August 2005, he took part in Battle of the Hockey Enforcers in Prince George, B.C. He lost to eventual champion Dean Mayrand in a round-robin split decision that Parker says many people thought he had won.
Parker went on to fight in a European version in October 2010, winning the show called Ice Warriors.
He remembers it fondly. A lot of the competitors were from the LNAH and they stayed at the same hotels, ate meals together and swapped stories.
Then there was the Regina hockey fight camp, which he ran for two summers after the late Derek Boogaard backed away from it because of averse publicity. Parker has also helped out the Regina Pats, educating them in the art of hockey fighting as a martial art.
A shade under six foot one, Parker normally walks around at 195 pounds.
He started "dabbling" in MMA back in 1999 thanks to the strength and conditioning coach of the Lethbridge Hurricanes. After taking part in some amateur fights in 2007, he realized after three losses that while he was long on toughness, he was short on technique.
"I learned that I had to learn that it's a new sport," he said.
He now trains at the Wiley Jiu-Jitsu Academy and at Siam Kickboxing and Muay Thai, both in Regina.
Deryl Bangsund, one of his striking coaches, says Parker showed him early on that he has heavy hands, athletic ability and toughness.
"He doesn't shy away from stuff," said Bangsund.
"Derek is uncannily focused," he added. "One of his largest strengths is his dedication to being the best whatever ... He strives for excellence."
In March, Parker won his pro debut by submitting Dave Bedard in Sherbrooke, Que., on an Instinct MMA card. In addition to his MFC deal, he has a contract with the Quebec organization so he can fight in front of his fans from the LNAH days.
Parker will be easy to spot at the Mayfield Trade and Convention Centre on Friday. He'll be wearing pink shorts as part of an anti-bullying statement — his slogan is "Be a hero, stop bullying."
Away from the cage, Parker has worked in the oil field as a process operator but is now focusing full-time on training. To make that happen, he is renovating and selling his house.
He plans to go to university in the fall and hopes to train with the University of Regina wrestling team.
As for the nickname The Lions, his middle name is Leo — which is also his zodiac sign.
He says he showed his fighting attitude right from the get-go. Born with bad asthma, he spent much of the first two years of his life in hospital.
"They actually thought I was dead twice," he said. "It made sense to me a little bit later when my Grandma Jones said to me 'I used to watch you fight for your life. Every breath we thought was your last and you had to fight. Now you're just fighting for fun.'"
The main event Friday is a fight for the vacant welterweight title between Edmonton's Ryan (The Kid) McGillivray (12-5-1) and American Nathan Coy (10-4).
McGillivray is bidding to become the first Canadian welterweight title-holder in the MFC's 12-year history.