Shepherd told the Evening Chronicle: "Michael was a great player, but financially it didn't turn out a good deal.
"I think at the end of the day when 20,000 people turn up just to see somebody sign and welcome him you know at the time it's a good deal.
"I didn't hear anybody saying, 'Don't buy him then'."
He added: "Hindsight is a great tool. Certainly with Owen it didn't work out as it should have. Injuries are injuries and this can happens.
"Would I do it again? The answer is no. But, as I say, that's with hindsight."
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