Manchester City defender John Stones will miss this weekend's game against Watford and will be out for around five weeks with a muscular problem, manager Pep Guardiola has announced.

The England centre-back suffered the problem in training ahead of their Champions League opener against Shakhtar Donetsk this evening.

"He (Stones) is out four, five or six weeks. He was injured in training this morning. It is a muscular problem," Guardiola said.

Stones' absence will add to the defensive problems for Guardiola, with French centre-back Aymeric Laporte already likely to be ruled out until the New Year.

"For me as a manager it is an incredible challenge. But I believe in something people don't know about - spirit and commitment. We will make steps forward to solve this problem," Guardiola added.

With his defensive options now severely limited, Guardiola could be reliant on midfielder Fernandinho filling in in place of his injured centre-backs, alongside Nicolas Otamendi.