De Zerbi is under pressure after OM were bounced out of the Champions League this week.
"This type of coach needs time," Riolo stated on his blog. "Players need great maturity to adapt to changes in formation and build different formations.
"(Mikel) Arteta did a lot of similar work at Arsenal, but he was given time, and the first few seasons were incredibly difficult. Luis Enrique at PSG only found consistency when he stopped constantly changing.
"De Zerbi needs to figure out if he has players mature enough to follow his concept of adaptability: switching from a three-man back to a four-man back from one game to the next isn't easy and often doesn't work."
Riolo also said: "It's impossible to explain some of their performances. On Wednesday, the team seemed convinced that even if they lost, they would advance, and they never really moved from the start.
"But when they want to..."
He added: "We need to decide whether to give him time or not. This coach needs time, and the club must be ready to give it to him. Only then will we see if OM can become consistent."