NEW YORK, Jan 14 (Reuters) - It is unlikely that credit spreads will return to levels seen before the financial crisis hit markets, Philadelphia Federal Reserve Bank President Charles Plosser said on Wednesday.

Plosser said credit spreads in the early summer of 2007 were unusually narrow.

"If the expectations was to get spreads back to that level, that is not the way to think about it," Plosser said, while answering questions from reporters after an economic outlook conference at the University of Delaware.

Plosser added that a challenge facing policy-makers is to decide what an "appropriate" spread level is, which would help the Fed to make decisions on an exit strategy from its emergency lending programs.

(Reporting by Kristina Cooke, Editing by Chizu Nomiyama)