Manchester United are expected to return with separate offers for Marouane Fellaini and Leighton Baines having incensed Everton with a joint £28m bid for David Moyes's former players.

Everton described as "derisory and insulting" an offer that valued Fellaini at £16m a decrease on what Moyes paid for the midfielder five years ago and Baines at £12m the sum rejected earlier in the summer. The offer was made late last week by United's executive vice-president Ed Woodward but sanctioned by Moyes leaving Everton's chairman Bill Kenwright furious at the valuation and its potential disruption to Roberto Martínez's debut season at Goodison Park.

United's joint bid as with their initial move for Baines in June was rejected out of hand by Everton but is unlikely to be their last approach having failed to make any senior signings so far under Moyes. Everton are adamant the England left-back is not for sale and want to keep Fellaini although an improved offer for the Belgium midfielder may test that resolve. United's prospects would therefore be improved by lodging separate bids for Everton's prize assets.

Everton's director of communications Alan Myers said: "Everton received bids from Manchester United for two players. Those bids were immediately rejected out of hand as derisory and insulting. The club did not make public these details as it was vital Roberto Martínez's preparations for the opening game of the Premier League season were not disrupted in any way."

Martínez may return to Wigan Athletic for James McCarthy in the event of Fellaini's departure and has inquired about signing Gareth Barry on a season-long loan from Manchester City. However the Everton manager says the club have complete control over Fellaini's future following the expiry of a £23.5m buy-out clause in the midfielder's contract on 31 July and will not sell below that price. The 25-year-old did not attract one offer while his buyout clause was in place strengthening United's conviction that £23.5m did not reflect his market value.