Both sides have won 2 of the last 5 but Leigh would probably consider themselves the favourites being at home and on the back of decent win at York the previous week.
Last time these two met the Championship Grand Final Trophy was on the line and the visitors left with the spoils. This season both sides are at the bottom end of the table, with York failing to beat anyone who doesn't come from Hull and Toulouse failing to pick up a win since February.
Cas come into this one off the back of moral boosting win away to Wigan that lifted them off the bottom of the table level with this week's visitors, who've had a couple of tough weeks losing their derby followed by a defeat against Saints.
Leeds sit top of the table and are in fine form of late. This week's visitors are only 2 points behind and won the last time they visited Headingley but sit on a poor run of away form in the league at the moment.
Two of the top clubs in the league face off with Wigan looking to turn around what's been a difficult April while the Wire are looking to bounce back from their defeat against the top side Leeds and get back on track to making this their year.
Amidst an injury crisis the third team to get promoted last season face the daunting prospect of the defending champions who are in a rich vein of form since their disappointing visit to the south of France last month.
Second v third should make for a tight match and both sides are unbeaten in the league in April. That said Trinity haven't found St Helens the happiest of hunting grounds recently and Saint had a 100% record against their visitors last year.