RHS council member Alexander-Sinclair replaced Wilson as RHS chairman of moderators at Hampton Court and was chairman of assessors at Tatton Park.
Alexander-Sinclair said the RHS needed a larger panel of judges but Chelsea is "made difficult because a lot people are involved with others in the show", which leads to potential impartiality issues.
"It's better to keep as safe as you can to avoid conflicts of interest," he said.
"I don't know about judging at Chelsea. You can't judge if you're on TV - it's all about conflicts of interest. I get paid for being on TV and I've not judged for the past couple of years. The make-up of judging panels is decided by the RHS shows department."
He said the judging process was changing, with accredited and trained judges coming in.
RHS shows head Bob Sweet said: "We don't know about Chelsea 2014 judges yet. At the end of the year we ask about availability."