Allison Coss and Scott Sippola were convicted in July of conspiracy and using e-mail to threaten a person's reputation. They were accused of demanding $680,000 from Stamos in exchange for turning over embarrassing photos of him.
The FBI says it never found any compromising pictures of Stamos. He met Coss in Orlando, Fla., in 2004 when she was 17.
Stamos starred on "ER" and "Full House," and now plays a dentist on Fox's hit musical "Glee."
He doesn't plan to attend Friday's hearing in Marquette. But prosecutors have requested permission to read a statement from Stamos.