"We don't have the slightest intention of selling him. We want him to be playing for Stoke City for many years to come," the chairman told British media.
Butland joined Stoke in 2013 and became a prominent member of the team in 2015, where he made 31 league appearances to help Stoke finish ninth.
Coates believes that the 24-year-old has more to offer.
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"In the last full season he had... he looked the most promising young goalkeeper in England," Coates said.
"We have only seen a relatively little bit of him since his return towards the end of the season, but during that short time we certainly saw nothing to discourage us about his abilities as a goalkeeper.
"And the fact that England recalled him to the national squad at the first available opportunity suggests he also has a bright future ahead of him on that front too."
(Reporting by Aditi Prakash in Bengaluru, editing by Nick Mulvenney)
