The England Under-21 international, whose five goals in three games in April played a major part in keeping the Black Cats in the Barclays Premier League, was due to be out of contract in the summer.
Had new terms not been agreed he would have been able to sign a pre-contract overseas in January, while closer to home the likes of West Ham and Crystal Palace have reportedly shown interest.
Wickham, who signed from Ipswich for £8.1million in 2011, has found the net three times in the current campaign, twice in the league.
Source : PA
Source: PA