Manchester City manager Roberto Mancini has admitted that he regrets not signing an extra defender during the January transfer window.

Captain Vincent Kompany has not featured for the Citizens since was injured in their FA Cup fourth-round win at Stoke City on January 26.

Mancini did not expect Kompany's calf problem to cause such a lengthy lay-off and he describes the 26-year-old's absence as "a big problem".

He said: "Probably we made a mistake because when we knew [of] this problem we were four days to [the] close [of] the market. Probably then we should maybe have bought another defender.

"Also, last year he had this problem - for one month he didn't play. This is a big problem. For me we did a mistake in this case.

"We had a chance because we had one good defender, but we didn't think that Vinny would stay out for 40-45 days."

Kompany will not feature in this weekend's match at Everton, but he could return when City host Newcastle United on March 30.