Kostas Manolas has joined Roma on a €13 million ($17 million) transfer from Olympiakos, as coach Rudi Garcia looks to strengthen his worrisome defense before Serie A starts this weekend.

Roma said Tuesday it had signed the center back to a five-year contract.

Manolas is an immediate replacement for Morocco defender Mehdi Benatia, whom Roma sold to Bayern Munich in a deal reported at €26 million ($34 million), also on Tuesday.