McKernan had made an encouraging debut against Richmond in round 14, 2009, but was denied the opportunity to add to his games tally when he broke his arm at training on the eve of the Crows' clash with Fremantle the next week.
The 20-year-old returned to the field six weeks later only to suffer another fracture in the same arm, which ultimately put an end to his season.
McKernan's second year at West Lakes also started promisingly.
He was one of few positives to emerge from Adelaide's disastrous NAB Cup campaign and recruiting manager Matt Rendell tipped the forward/ruckman to become a regular in the team that season.
He got close to breaking into the side, being named as an emergency in rounds three and four but by the halfway-mark of the 2010 season was yet to crack a second AFL game.
His form for battling SANFL club South Adelaide and on the track with the Crows was good without being outstanding.
He showed enough through his raw athleticism, occasional big mark and odd bag of goals to suggest he was capable of much more.
However, it wasn't until something in his mind clicked towards the end of last season that he was able to deliver on that promise more regularly.
"Towards the end of last year, I had to re-assess where I was at," McKernan told afc.com.au.
"In my first year at the club I was probably finding my feet, but last year I could've gone in and trained a bit harder.
"I changed my mindset in regards to how I went about training and just my attitude towards training and what I wanted to get out of it.
"Craigy [coach Neil Craig] always used to say to me, 'make sure you get the best out of your training'.
"He would say it to me over and over and it started to sink in late last year."
McKernan's form in the SANFL also improved as a result of his decision to "attack" rather than just complete training.
The former second-round draft pick forced his name back in front of the Adelaide match committee, being named as an emergency and narrowly missing out on selection in the last three rounds of the season.
"It was a bit disappointing not to get a game [towards the end of the season], but I learned a lot from the things that didn’t go my way," he said.
"I really set myself and said, 'if this is going to be my last year [in the AFL] I want to at least try and have a crack and go out well'.
"I wanted to make sure I got the best out of everything over the pre-season. Looking back on it I think I did and it's starting to pay off now."
McKernan starred in the pre-season competition and played his long-awaited second game in front of former North Melbourne/Carlton champion and older brother Corey, against Hawthorn at AAMI Stadium in round one.
McKernan has played every game since, lining up alongside Kurt Tippett and Taylor Waker in attack and also as pinch-hitting in the ruck.
He sits third in the Crows' goalkicking (six goals) and is ranked top-10 in the AFL for contested marks, but is not content with his impressive start to the season.
"I feel a bit more confident and comfortable, but I still have a long way to go until I feel right at home and really set myself in the team," he said.
"I know there's still a lot more I can get out of myself."
McKernan is also feeling more comfortable away from the football field.
He lives with teammates Rory Sloane and Jared Petrenko in "one of" midfielder Bernie Vince's properties and has started a part-time business course.
Far from being delisted, the out-of-contract Victorian is likely to attract the attention of rival recruiters this season but said he was keen to stay with the Crows.
"I'm pretty happy with where I'm at and don't intend on going anywhere," he said.
"I miss everyone back home, but I've got a lot of people here now, who I can talk to and have made a lot of mates. I'm pretty happy in Adelaide."
