Martinez played with Griezmann at La Real.
"Griezmann will provide insurance at Barcelona," Martinez told Radio MARCA.
"He's going to be a great player because he's proved it [in the past]."
The 33-year-old, who currently plays for Burgos in the Segunda Division B, makes the case that Real Sociedad need to be at their best in order to emerge with a victory on Saturday evening.
"La Real are playing some very nice football, they have a lot of quality," Martinez added.
"To beat Barcelona, they have to [play well]."