Vaz Te failed to get a move away in the final week of the summer market after submitting his transfer request.
Cottee told the Daily Star Sunday: "I know he can say that he was being played out of position but that is what happens in modern football.
"I was hoping that a deal could be done for him to go out, so that we could bring in another striker which we badly needed. But it is so difficult when you leave things to the last day and you have to make sure you have one coming in before you let another go.
"Sam Allardyce obviously rates him as he's signed him twice, so he needs to show the right attitude from now on."
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