Manchester City are expected to make an improved offer for Jonny Evans after West Bromwich Albion rejected a bid worth an initial £18 million for the Northern Ireland and former Manchester United defender.

Pep Guardiola has identified Evans as a shock target as he bids to add another centre-half to his squad and make the 29-year-old his seventh signing of a dramatic summer overhaul.

City made the offer - which was understood to be worth at least £20 million including add ons – late last week only to be rebuffed by West Brom, who have been hoping to tie Evans to a new £85,000 a week contract after their captain entered the final two years of his existing deal. Evans would boost City's homegrown quota of players.

Evans, who was not in the West Brom squad for Saturday’s 1-0 win at home to Bournemouth, is also thought to have been the subject of an earlier offer from City and a £10 million bid from Leicester.

West Brom’s official stance is that Evans is not for sale, and given that the club are operating with a relatively small squad, they may only consider letting Evans leave if Tony Pulis manages to sign a replacement first.

Evans is a former Manchester United player

But the Midlands club – who rebuffed interest in Evans from Arsenal last year - now face a serious fight to keep hold of one of the Premier League’s most underrated defenders, even if it could take around £30 million to prise him away.

City have so far balked at Southampton’s £70 million valuation of Holland centre-half Virgil van Dijk while another long-standing target, Italy defender Leonardo Bonucci, joined AC Milan from Juventus this summer.

United sold Evans to West Brom for £8 million two years ago when Louis van Gaal was in charge and the Northern Irishman has since excelled for Pulis and formed an impressive partnership with compatriot Gareth McAuley.

Guardiola is thought to admire Evans’ ability on the ball and sound positional sense and believes his long-standing experience in the Premier League and Champions League make him an attractive proposition given his eagerness to play with three at the back on a regular basis this term. His signing would also boost City's quota of homegrown players.

Vincent Kompany has a terrible injury record

With Eliaquim Mangala, who is attracting interest from Inter Milan, and Jason Denayer, who has so far refused to join other City youngsters on loan at Girona, surplus to requirements, Guardiola wants proven cover for Vincent Kompany, Nicolas Otamendi and John Stones.

Kompany’s dismal injury record over the past two seasons means City can also not bank on the fitness of their captain and Evans would provide genuine competition for places. If Evans arrived, it could increase the chances of youngster Tosin Adarabioyo being sent out on loan.

Guardiola has spent almost £220 million on six players this summer, including the purchase of three full-backs, Kyle Walker, Benjamin Mendy and Danilo.

But that figure could rise to around £300 million if City manage to lure Evans and are also successful in their pursuit of £60 million rated Arsenal forward Alexis Sanchez, for whom they are expected to lodge a formal bid shortly.