Saarijarvi has four goals, six assists and is plus-6 in 11 playoff games. One of his goals was a game-winner.
During the regular season, Saarijarvi had 11 goals, 20 assists and was plus-20 in 34 games with the Steelheads.
Saarijarvi had a successful first season in the OHL with the Flint Firebirds last year, despite some turmoil on the team with the owner.
In August, Saarijarvi talked about the situation.
"I did ask for a trade but it wasn't anything personal against Flint," Saarijarvi said. "I don't have anything against the Flint team, I just thought it's going to be best for me. I talked to the coaches in Flint and I think they knew the situation, too. I just felt it was the best for me at this point. It's something that happens in hockey."
Saarijarvi was traded to the Steelheads in the offseason.
Saarijarvi, who turns 20 next month, is one of six finalists for the Max Kaminsky Trophy, awarded to the OHL's top defenseman.
The other finalists are Santino Centorame (Owen Sound), Ryan Mantha (Niagara), Darren Raddysh (Erie), Mikhail Sergachev (Windsor) and Matthew Timms (Peterborough).
Defenseman Jordan Sambrook, the Wings' fifth-round pick, 137th overall, in last summer's draft, plays for the Erie Otters, who will face the Owen Sounds Attack in the Western Conference finals starting Friday.