Sunderland will have to come up with more cash if they are to prise striker Jozy Altidore away from AZ Alkmaar. Press Association Altidore, who made 28 Barclays Premier League appearances on loan at Hull from Villarreal during the 2009-10 season, scored 23 goals for AZ last season to attract the attention of a series of potential suitors. However, Sunderland have struck the initial blow and will hope to follow it up with a decisive move as manager Paolo Di Canio attempts to radically re-shape his squad. The Italian, assisted by director of football Roberto De Fanti and chief scout Valentino Angeloni, has wasted little time in ringing the changes at the Stadium of Light. His players returned for pre-season training today with new boys Valentin Roberge, Modibo Diakite, Cabral and David Moberg Karlsson added to the mix, and more signings are imminent as the club closes in on keeper Vito Mannone, young full-backs Gino Peruzzi and Benjamin Mendy and midfielder El-Hadji Ba. But the striking department will be a particular focus after Steven Fletcher’s ankle surgery, which ruled him out of the final eight games of last season, emphasised the club’s relative lack of depth. Former boss Martin O’Neill invested £5million in Swansea’s Danny Graham in an effort to address the problem, but he failed to score a single goal in his 13 appearances at the end of the campaign. Stephane Sessegnon’s future on Wearside remains uncertain amid speculation the club could cash in on him this summer, while Connor Wickham and Ji Dong-won are yet to prove they can do the job on a sustained basis. The Black Cats have tabled an initial bid for the 23-year-old United States international, although there have been conflicting reports over whether or not it has been rejected. However, Press Association Sport understands that the Dutch club has rebuffed Sunderland’s offer, which fell some way short of matching its valuation of the player. But having registered their interest formally, the Wearsiders are regarding the rejection as the first salvo in the battle to land a player identified some time ago as the man to freshen up their attacking options.