The Hamamatsu brand sent shockwaves through the grand prix paddock earlier this year by announcing the end of its factory involvement in MotoGP despite winning the title as recently as 2020 with Joan Mir.
With Suzuki also preparing to end its factory support for the multiple title-winning SERT outfit in EWC, it is set to leave the marque with no representation in any major international motorcycle series in 2023.
Denning served as team manager for the final years of Suzuki's previous stint in MotoGP, taking the role in late 2004 and staying on board until the firm pulled out of grand prix racing at the end of the 2011 season.
Since then he has focused on running the family-owned Crescent Racing squad in WSBK, firstly with works backing from Suzuki before switching to become the factory Yamaha team in 2016.
Having already experienced Suzuki pulling out of MotoGP once, Denning said his reaction to the news of the marque quitting again was one of "disappointment rather than surprise" in an interview with Motorsport.com's German edition.
"I’ve been there before, as has [Shinichi] Sahara-san [MotoGP project leader], who is going through it a second time," continued Denning.
"At the start of a five-year contract with Dorna, days away from signing a contract with a rider… there is no connection between Suzuki’s racing programme and senior management.
"In the end I’m a Suzuki fan, we [Crescent] still have a Suzuki shop in the UK, which we've had since 1963. So not really surprised, just disappointed."
Suzuki's withdrawal from MotoGP comes as speculation mounts over the future of its flagship GSX-R1000 street bike, which is set to fall foul of new European emissions restrictions next year.
Although Suzuki has not had a factory presence in WSBK since 2015, a new version of the GSX-R1000 was homologated in 2017 and remains eligible for the series through the 2026 season.
The GSX-R600 and GSXR-750 models are also homologated for World Supersport, although neither are currently used.
Asked if he expected a future Suzuki racing comeback, Denning replied: "Possibly not. They still have good street bike models, and they are nice bikes, but the desirability of Suzuki will continue to decrease.
"I think it’s a very short-term approach by the senior management. But I’m not surprised."
