Fryatt signed for Forest this week.
Writing in the Nottingham Post, Birtles says Fryatt can become a leading goal-scorer at Forest from next season and beyond.
"Firstly, he can be a 20-goal striker for the Reds next season. He can be the player we have been waiting to sign for years.
"Secondly, they signed him on a free transfer.
"If those two things added together are not reason to give Stuart Pearce a bit of a pat on the back, I don't know what would be. It is a fantastic signing."
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