Manchester City defender John Stones is set to miss high-profile Premier League fixtures against title rivals Manchester United and Tottenham Hotspur next month after manager Pep Guardiola confirmed fears that a hamstring injury would likely keep the increasingly influential centre-back on the sidelines until 2018.
Stones has played a prominent role for City so far this term, starting 16 games across all competitions and helping the dominant leaders build an already unassailable-looking eight-point advantage at the top-flight summit.
He was paired alongside returning captain Vincent Kompany for Saturday's (18 November) clash with Leicester City with usual partner Nicolas Otamendi suspended, although had to be replaced by Eliaquim Mangala 31 minutes into a comfortable 2-0 victory at the King Power Stadium after receiving treatment on the pitch.
Guardiola estimated that a muscular issue would force England's Stones to miss at least four weeks and suggested the club would discuss the possibility of procuring further defensive reinforcements in January to address a "real, real problem" amid links to Southampton's Virgil van Dijk.
He also spoke of the risk of exposing Kompany, who played the full 90 minutes at Leicester after controversially avoiding an early red card, to more minutes after two-and-a-half months out with yet more calf trouble.
Addressing the injury again at a press conference held before Tuesday's [21 November] Champions League visit of Feyenoord to the Etihad Stadium, Guardiola said: "John will be out between four up to six weeks. All of the month he will be out but hopefully he will recover well for start of January."
In addition to the Manchester derby against Jose Mourinho's second-place United at Old Trafford on 10 December and the home meeting with Tottenham six days later, a six-week absence would also see Stones remain absent for matches against Huddersfield Town, Southampton, West Ham United, Shakhtar Donetsk, Swansea City, Leicester, Bournemouth, Newcastle United and Crystal Palace.
Guardiola will now have to rely heavily on Kompany and Mangala, the latter of whom spent last season on loan at Valencia and has made just two substitute appearances in the league since being denied a summer exit. He also stressed that right-back Kyle Walker and midfielder Fernandinho were both capable of operating in central defence and hinted that there could be an opportunity for 20-year-old academy graduate Tosin Adarabioyo.
"We don't have a big squad," he said. "We lost Vincent Kompany in an international game and now, John Stones. It is not easy to play 12 games in a short space of time. I will like seeing how we will react - how players will play in different positions than they are used to playing. Tough situations.
"When things are comfortable, that is not a lot of credit. I want to see how we will react. Maybe Tosin Adarabioyo is another option. We will see. It depends on the players. We have Tosin, Brahim [Diaz] and Phil [Foden] training will us from the beginning of the season. They have a chance to play, of course."
The 2015-16 semi-finalists City have already secured their place in the last 16 of Europe's elite club competition with two matches to spare and could seal top spot in Group F with a fifth straight triumph over Feyenoord.
Foden and Diaz could play some part against the defending Dutch champions, while Guardiola revealed that the ruptured anterior cruciate ligament suffered by summer signing Benjamin Mendy in September is the reason why strikers Gabriel Jesus and Sergio Aguero are no longer being deployed together in the final third.