The belief has never left Leek Aleer.

Stranded in the VFL through the first 10 weeks of the season, and restricted to just 12 games through his first three years on the club's list, it would have been easy for the GIANTS talented defender to get down on himself.

However, Aleer has instead viewed his stint in the reserves through a positive lens. While it might have been somewhat frustrating, the leaping 194cm defender was part of a GIANTS VFL program that went unbeaten through its first six games of the year and relished the chance to find rhythm in a thriving team.

Then, last Saturday, he made the most of both the rich vein of form he had worked himself into, as well as an opportunity at AFL level. His role proved pivotal as the GIANTS dispatched the Blues to move to 6-5 on the season.

"For me, personally, it was more so around playing well," Aleer told AFL.com.au.

"I had to keep my head up and keep trying to do the things that I've been strong at, especially in the VFL. Obviously, the positive side of that is the fact that the VFL program has been going well.

"We have a lot of AFL-listed boys in the VFL, so it's quite an enjoyable place to play. It's not all doom and gloom. We were winning games, it's a young squad, so for me I've found it pretty easy to hold my head high and continue to work hard."

Playing for the first time at AFL level in 322 days, Aleer impressed in Saturday's comfortable 28-point win. He finished with five marks, two intercept marks and eight spoils to help thwart Carlton's wayward attack.

"They told me I was a sniff early on in the week," Aleer said.

"I trained well Thursday and they told me I was in. I was pretty excited.

"For them, it was more around me coming out and playing to my strengths. I had to do my best in terms of defence, and just focus on defending first and then supporting as much as I possibly can in the air. Everything would happen off the back of that. That was the main message.

"I thought, as a collective and as an individual, that was done well."

Aleer, who started the match on Carlton's Charlie Curnow, was involved in an ongoing game of cat and mouse throughout much of Saturday's encounter. The Blues, in attempting to win a favourable matchup, continued to try and push Lewis Young to All-Australian Sam Taylor so Aleer would have to mark Curnow.

Eventually, though, the GIANZTS won out. Aleer went to Young, and then later Mitch McGovern after a half-time rotation, enabling Taylor to thwart Curnow's influence for much of the second half.

"We were trying to free each other up and it was a bit difficult," Aleer said.

"They both held on for a little bit trying to get that matchup they wanted. But we held on and then, in the end, we ended up being free. It was quite jarring at the start, but it ended up being to our benefit at the end.

"Sam is terrific, he's just terrific. I love playing with him. He's arguably the best key defender in the competition. I've learned so much from him and Jack Buckley and all of the other backs as well.

"There's so much depth in our squad. Playing with them week-to-week, I definitely enjoy it. There are always a lot of key lessons to take out of every situation and I enjoy that. I love them."

So, after all of the hard work to get back into the side – Aleer played seven consecutive reserves fixtures to start the year, averaging 14.3 disposals and 6.3 marks – will he manage to retain his place in the AFL team?

"I thought he did really well tonight," Kingsley said afterwards.

"After quarter-time, I thought he was really good. He had a mix of tall and small (opponents), some really critical spoils, he was head and shoulders above everyone else and punching the ball out of the danger zone.

"He just needs to keep playing to his strengths. That's what we'll ask him to do. I thought he was really good tonight. I would imagine he would hold his spot next week. Lachie Whitfield shifting into the midfield also supported us, too.

"We'll have some decisions to make. That's the nature of having a few good players in different spots."