Pep Guardiola has said Manchester City could be “in trouble” following John Stones’ latest injury. The treble winners are awaiting an assessment of the England defender after he was forced off with a knock in Tuesday’s 3-0 Champions League stroll against Young Boys. Stones only returned to action in October after a two-month absence with hamstring and hip problems. Manager Guardiola said he feared the 29-year-old could be out “for a while” with the muscular problem and described the blow as “deep bad news”. Stones has shone for City playing in a hybrid defence-midfield role and Guardiola feels he perfectly complements the central midfield anchor Rodri. Much was made of the fact Rodri was suspended when City lost three successive games earlier in the campaign, but Guardiola believes the absence of Stones was equally crucial. He said: “The problem is we play John and Rodri at the same time - now we are in trouble, because we have to play a bit differently, like happened in Arsenal. We do not feel comfortable still, we are not prepared to change many variations.” City hardly broke sweat as they brushed aside the Swiss champions to secure their place in the last 16 for an 11th consecutive year. The holders have won all four of their matches in Group G and are through with two matches to spare. Erling Haaland made light of the twisted ankle that curtailed his involvement against Bournemouth last weekend to open the scoring with a penalty, and added the third goal with a powerful long-range strike. It was yet another dominant performance from the Norway striker, who has now scored 39 goals in 34 career Champions League appearances and 15 in all competitions this season. The opposition captain, Mohamed Ali Camara, asked to swap shirts with the 23-year-old at half-time, which drew criticism in some quarters. “I’m a little bit surprised about that right now,” said Young Boys coach Raphaël Wicky, whose side failed to muster a single shot and had midfielder Sandro Lauper sent off in the second half. “I’ll probably have a word with him.”