**Edinburgh could go top of the United Rugby Championship when they host Cardiff on Saturday.** Not since the 2009-10 Celtic League season have the Scottish capital club reached the summit of a combined league table. However, with Leinster - who top the table by a point - not in action this weekend, second-placed Edinburgh have an opportunity to leapfrog the defending champions. Henry Immelman, James Lang, Blair Kinghorn and WP Nel all return from injury for Mike Blair's side, while Cardiff - boosted this week by the signing of Scarlets full-back Liam Williams from next season - make seven changes from their last URC outing in October, with Rhys Priestland among those returning.