The powerful Socceroo has been limited to just 12 games, and six starts, in a season where recent powerhouse City had to fight just to make the finals.
Leckie missed the start of the season with a contact knee injury suffered on Socceroos duties, then later missed separate chunks of City's campaign through a hamstring strain, then an adductor injury.
"It was definitely a difficult season for myself," Leckie told AAP.
"It was just one thing after the other, so it was frustrating at the time.
"When the team's not doing well, you also want to be playing, and it's hard to watch when we're getting bad results."
City have won all three of Leckie's starts since his return from injury, sealing their finals berth.
Since his return, he's also been moved into the midfield, where he has excelled.
"Although I've missed most of the season, it was nice to be able to come back and contribute to the opportunity to make finals," Leckie said.
"If anything, I've just tried to really win the battle out there in the midfield and tried to control the midfield."
He believes City can deliver this finals series, starting with Sunday's elimination final against Melbourne Victory at AAMI Park.
"We have the potential to do it with the players that we have," Leckie said.
"In the last two months we've really changed the mindset, sort of a little bit tactically how we're playing as well.
"Since we made that change we've been really good.
"We're full of confidence to be able to maybe surprise a few people."
City will farewell Jamie Maclaren and Curtis Good when their season ends.
Leckie, whose three-year deal ends in June, has been more focused on stringing games together than chasing up his next deal.
"Obviously it's something that you'd probably like to sort out, but obviously it's been a tough season and I haven't really played," he said.
"So for me it's been more speaking to my agent about just getting fit again and then see what happens.
"I haven't really spoken too much about it with the club, but I've really enjoyed my three years here, so it's definitely somewhere I would stay."
Mathew Leckie would love to play more representative games for the Socceroos. (Dean Lewins/AAP PHOTOS)
Leckie, 33, is also still keen on a Socceroos return, despite his hamstring injury ruling him out of January's Asian Cup.
"I've made it pretty clear that I've always loved playing for the national team," he said.
"I would definitely love to play a part in helping the team, if Arnie (coach Graham Arnold) thinks I can still help the team.
"Whether I'm fit and able to play in the next World Cup doesn't really go through my mind, it's irrelevant whether I play there.
"I still want to play my part helping the team potentially qualify for the next World Cup, so we'll see what happens."
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