West Ham United have to take advantage of the absence of Chelsea goalkeeper Petr Cech on Saturday.
That is the view of former Hammers and England stopper Phil Parkes, who believes the absence of the injured Czech Republic international opens a window of opportunity for Gianfranco Zola's side. With back-up Hilario also sidelined, former Middlesbrough stopper Ross Turnbull is in line to make his first league start for the Blues.
Whoever lines up between the sticks for Carlo Ancelotti, the 1981 Hammer of the Year believes West Ham must get back at least one of the points they lost by losing at home to Bolton Wanderers when they travel to Chelsea and Arsenal over the coming two weekends.
"Chelsea is probably the tougher of the two, as Arsenal tend to let you play football, as we've seen in our two meetings at Upton Park, where we've had two good games against them. Obviously, with the strikeforce that we've got, maybe we can give them even more of a game.
"Chelsea will be a tougher game because they do close you down and, when they are on their game, they are a formidable side. But this is a good time to play them because they've got a few injuries, including a bad one which could set them back a bit to Cech.
"I think we've got a chance, especially with the bit of belief we've got now and the strikeforce we've got. When was the last time we had two strikers come off and two strikers come on, like they did against Hull City? It's been unheard of here and it bodes well."