"Unfortunately, (barrier) 17 over 2400 metres at Mornington, we didn't feel it was right," he said.
"He needed a nice barrier. Last start he drew well and we ended up too far back, so we decided to scratch from Mornington, and we will head towards the 2000-metre race at Flemington on Saturday.
"After that, and depending on his performance, he could then head towards the Warrnambool Cup."
The Listed Warrnambool Cup (2350m) will be run on May 7 and is a race that Lindsay Park won in 2019 with Furrion when David and Ben Hayes and Tom Dabernig were on the training ticket.
Plymouth had been racing well prior to his most recent performance.
He finished second in the Listed Albury Cup (2000m) on March 20 before finishing a last start 12th of the 14 starters behind Ambassadorial in the Group 3 Easter Cup (2000m) at Caulfield on April 3.
"He's fine and it was just the barrier why we didn't run," Hayes said.
"It's very hard from out there, especially at Mornington."