Maro Itoje is a doubt for England’s crunch Guinness Six Nations clash with Ireland at Twickenham on Saturday after becoming unwell overnight.

Itoje will miss Friday’s captain’s run at the stadium but England are “cautiously optimistic” that he will be available to take on Andy Farrell’s title rivals.

In a second blow to the squad on the eve of a pivotal match, forwards coach Richard Cockerill has tested positive for Covid-19 and is now self-isolating.

England will be hoping that Itoje recovers sufficiently to take his place in the second-row knowing that they cannot afford to lose a player of his calibre if they are to defeat Ireland.

A mainstay of Eddie Jones’ pack, Itoje sets the physical tone for his team, particularly in defence.

At this stage England have opted against calling up any cover in the event Itoje is ruled out, but Joe Launchbury would most likely step up from the bench to fill the void.

Launchbury is still on his comeback from a serious knee injury, however, as he prepares to make his first international appearance since December 2020.

Another option would be to recall Nick Isiekwe from Saracens and slot him straight into the starting XV given he will be more battle-hardened than Launchbury due to his regular involvement in this Six Nations.

Leicester rookie Ollie Chessum is present as a reserve, but picking him on the bench against Ireland might be a gamble Jones is unwilling to take.