The 27-year-old improved his professional record to 12-0 thanks to a comfortable victory over Bulgarian Radoslav Mitev at the O2 Arena, in London.
Fitzgerald - who is due to face Fowler next month at the Liverpool Arena in a huge domestic super-welterweight contest - was far too strong for Mitev who has now lost 47 of his 61 pro bouts.
The Larches and Savick ace pierced the Bulgarian defences early on with a few stiff left jabs and as the opening round came to a close, Mitev was down after a right-hand to the head.
Just over a minute into the second round, Fitzgerald sent his opponent to the canvas once again thanks to searing left uppercut, which drew blood from his nose.
The Bulgarian failed to beat the count and Fitzgerald can now look forward to his meeting with Fowler on March 30.
Afterwards Fitzgerald said: "I wanted to go through the process tonight. If I hadn't of done, by the time March would have come around it would have been half a year since I last fought.
"I have been walking around in a bit of a bad mood so it was good to get it out of my system.
"I just go again now, train hard for eight weeks' time; carry on like I have been doing.
"Everything has been perfect and I will be more than ready to go and win that fight and push on for those titles."