The six-foot-two, 237-pound linebacker's preparation for the 2015 season is well underway but for the first time it's with the intention of being a CFL starter.
The Toronto Argonauts drafted Greenwood third overall in 2010 out of Concordia. But the 29-year-old Kingston, Ont., native joined the NFL's Kansas City Chiefs as an undrafted free agent, playing three seasons there and spending the '13 campaign on injured reserve with the Detroit Lions before being released Aug. 8, 2014.
Greenwood finally joined the Argos on Oct. 28, playing in their final two regular-season games. He'll get the chance in training camp to become a full-time starter after Toronto sent starting Canadian middle linebacker Shea Emry to Saskatchewan for defensive end Ricky Foley on Saturday.
"Every off-season is kind of like, 'Get back to the grind, switch your mindset, get out of vacation mode, it's time to get back to work,'" Greenwood said in a telephone interview. "But I think this off-season is a little different with what happened on the weekend.
"I went into the off-season with the mindset it's going to be an open competition at linebacker . . . but I feel like a door has been opened for me. I've really been waiting for this opportunity since I started playing professional football. I'm really excited about it."
Greenwood's time in Kansas City was spent mostly on special teams but Canadian university football's top defensive player in '09 logged plenty of reps at linebacker on the Chiefs' scout team that he says served him well.
"I don't know if I got a fair shot in the States because it's hard to get playing time when you're backing up Derrick Johnson, he's a Pro Bowl player," Greenwood said. "But I learned a lot there as far as technique and I was always playing against our first-line offence using those techniques to shed blocks and make plays.
"You can't be a pushover in practice because they'll get you out of there pretty quick if you don't want to compete. You're playing special teams but you're just an injury away from having to play. They're still coaching you and bringing you up to speed on everything."
Greenwood missed the entire 2013 campaign with Detroit recovering from shoulder surgery. Being able to practise and play in Toronto defensive co-ordinator Tim Burke's defence for two weeks following such an extended layoff was crucial — physically and psychologically —for Greenwood.
"It was good to get in there and start throwing my body around a little bit and get back to playing football," he said. "After being off the whole year and watching people play, I was just itching to get back in there.
"As an injured guy, getting back on to the field is all you can think about in the off-season."
One reason why Toronto could deal Emry, a native of Richmond, B.C., and two-time Grey Cup champion, was its Canadian depth at linebacker. In addition to Greenwood, the Argos also have James Yurichuk of Brampton, Ont., and Winnipeg's Thomas Miles.
"I know in their minds they think this is also their opportunity," Greenwood said. "It's going to be a really competitive camp and that's great because it's going to bring out the best in all of us."
Toronto GM Jim Barker, who was the club's head coach when it drafted Greenwood, said the former Concordia star will get the opportunity to earn a starting position.
"From our standpoint he's a guy who's got quiet leadership skills and his athletic ability is unquestioned," Barker said. "The coaches felt last year he picked up the defence well.
"He's going to make this opportunity or he's going to break it. It's in his hands."
It's an opportunity Greenwood says he has long wished for and is anxious to make good on now that it's here.
"When I went to the U.S., in my head I wanted to prove I was more than just a special-teams player," he said. "Even when I was down there, I was thinking 'I know my time here isn't going to last forever.' I mean, the (NFL) stands for Not For Long so I was always prepping in my head that I couldn't wait to go make a little splash in the CFL.
"I grew up with (Saskatchewan slotback) Rob Bagg and have always watched him as well as Cory Watson (a former Concordia teammate now a receiver with Winnipeg). I've gone into the off-season like it's my job to lose. Everything that sets you up for a good season is what you do in the off-season when people aren't watching and that's my mindset."