This article is part of Football FanCast's The Chalkboard series, which provides a tactical insight into teams, players, managers, potential signings and more...

When Crystal Palace travel to West Ham this Saturday, they will be slight underdogs given how things have turned out so far this season.

The Hammers have lost just once in seven Premier League outings, and that defeat came against Manchester City of all teams - Manuel Pellegrini's side have been excellent so far and rightly sit 5th in the table.

The Eagles haven't been much worse, in fairness. A solid start to the campaign has Palace sat 9th, just one point off the Irons.

Roy Hodgson's men, in that respect, must take advantage of one glaring weakness in the West Ham side.

What is the weakness?

Pellegrini had to watch on against Bournemouth as his No.1 and reigning Hammer of the Year Lukasz Fabianski went down injured, with the Pole now set to be out for just under three months in a cruel blow to the club's ambitions for the season ahead.

His replacement? Summer signing Roberto.

The 33-year-old has only made three appearances for the club since signing, with two of those coming in the Carabao Cup and one after replacing Fabianski off the bench - not so impressively, he has conceded five goals and kept his only clean sheet against League Two Newport County.

The Spaniard also doesn't have the best record at some of his previous clubs.

Roberto conceded a whopping 132 goals in 88 appearances for Real Zaragoza - picking up 10 yellow cards as well - while he also shipped 51 goals in 34 games for Malaga.

How can Palace take advantage?

Simply make life difficult for the experienced stopper.

Pummel his goal with shots and follow in, just in case he spills the ball.

Crowd him at corner kicks, perhaps sticking Cheikhou Kouyate or another physical presence in his way to make things hard for him.

Roberto's last start saw him concede four goals to Oxford, where he didn't even dive for any of the shots that went in.

Hodgson really should be making the Spaniard a key topic of his pre-match instructions, for there is quite obviously a glaring weak spot in the Hammers' XI.