"With my ankle, I had to come back through reserve grade at the start of the year as I didn't play any pre-season games.
"The physio held me back through the pre-season and in hindsight was a good thing but then I dislocated my finger after a few games back and rolled my other ankle.
"It was a horrendous start to the year but I got past it and there were a few demons I had to get past after that as well to get to this weekend."
Ainslie coach Chris Rourke is Jed's father's cousin and the Tricolours played an instrumental role in getting him to relocate to Canberra from Melbourne, where he spent time on the Casey Scorpions' (now Demons) VFL list and played one state league game.
Rourke can't speak highly enough of Costigan and the work he has put in to reach the 100-game milestone.
"Jed's one of those very popular players with his team members and the boys really get around him when he's off the park," Rourke said.
Ainslie AFL Canberra player Jed Costigan is playing his 100th first grade game for the club this weekend.
"He's just one of those blokes you love to have on your team. Through a few connections and some chats with his dad, we thought it would be a good place for him to come and play."
A win over the Jets would open the door for the Tricolours to edge closer to a top two finish and a second chance in the finals.