Sterling has started just two of City's seven Premier League games so far this season.
Despite his lack of starts, Gareth Southgate named the 26-year-old in his starting XI for Tuesday's World Cup qualifier against Hungary and Keane says while the England boss still trusts Sterling, something is untoward in Manchester.
"He's (Southgate) is a big fan of Raheem, no matter his problems with his club," Keane told ITV.
"He's got huge confidence in Raheem, he's never going to let him down, he was always going to start tonight...
"There's obviously some bust-up with Pep, there's something going on there, they've brought Grealish in (for £100m in the summer).
"You say 20 months left on his contract but 20 months is a long way away - he just needs to focus on his game."
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