Everton are on the hunt for a new goalkeeper in this transfer window.
Joel Robles has deputised since first choice Tim Howard was struck down by an injury which means he will be about for at least another month.
Martinez hopes to bring a keeper in on a long term basis and is particularly interested in QPR's Alex McCarthy and Cardiff's David Marshall.
Martinez looking for long-term signing
The Toffees boss stated: "There are a couple of options I feel could fit really well but I wouldn't just bring in anyone who stops the development of a youngster.
"I would rather make it a long-term signing. I don't think short-term would be a solution for us now."
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A goalkeeper is just one of the problems Martinez will have to worry about in the transfer window.
Everton currently sit 13th in the table having lost six of their last eight Premiership games including losing the last four games on the bounce.
The Toffees have already drawn up a shortlist of potential replacements for Howard who has also attracted MLS interest.
Also thought to be on Everton's shortlist are Ali Al Habsi and John Ruddy, according to the Daily Mail.
The most probable purchase would be Alex McCarthy as he has featured just twice for QPR since moving to the Rangers in the summer however it will depend on whether Redknapp will be willing to let a summer signing leave so soon after joining the Loftus Road outfit.