Irwin made his BSB debut with PBM Ducati in 2016 and was in his second spell with the team after rejoining in 2023.
He wished Scott Redding, the 2019 BSB champion who replaced Irwin while he was injured, all the best for the remainder of the season and said there were people at the team who would be “friends for life”.
Irwin will return to the grid at Thruxton after agreeing a deal with OMG Racing, who run reigning riders’ champion Kyle Ryde.
The three-time BSB runner-up said he “can’t go too much” into the reason for his departure but added: “It’s an expensive sport, maybe that has something to do with it, I don’t know.”
“There’s one bike and this sport is expensive. It’s a big ask to put two Ducatis out.
“It’s been really tough. When you work so hard to come back from injury you want that encouragement when you get positive news.
“When you go to trusted medics, I certainly value what they say. These are the guys you are trusting with your life.
“I know what I’ve been doing in training and it’s been great. I’m fit to ride and hopefully we can show that this weekend.”
