The striker suffered the injury during Manchester City's preseason win over Hearts on Friday and says he will now be sidelined "for a few months."
The 28-year-old suffered the injury during City's 2-1 win over Hearts on Friday and is now set to miss the start of the Premier League season.
The Spaniard wrote on his Instagram page: "I want to let you know that its going to be hard for the next few months, I fractured my fifth metatarsal and will be out a few months. I will be back stronger than ever."
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After scoring 23 goals in all competitions last season, Negredo had been linked with a return to Spain this summer. But, earlier in July, the forward insisted that he will remain with the Premier League champion.
"I don't want to leave City," Negredo said. "I'm very happy and very settled here. I had a difficult end to the season and that's why there has been a lot of talking but I've been very happy here from the first day I arrived."