Eto'o made a losing debut at Everton yesterday.
Shipperley told talkSPORT: "When players come from obscure clubs you do have doubts about him.
"If a player comes from a massive club you think he has still got it. So, in a way, Samuel Eto'o has got a bit to prove.
"He'll be buzzing to link up with Jose Mourinho again and to prove that he can score in the Premier League."
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