The 21-year-old was substituted with an apparent issue at the Madejski Stadium on Tuesday evening.
Everton ran out 2-1 winners against Reading in the Capital One Cup on Tuesday night, but not before star defender John Stones was forced to leave the field with an apparent injury early on in the second half.
The England international has been in inspired form for the Toffees so far this season, and the sight of him having to abandon the contest was an understandably worrying one for the club's supporters.
However, speaking after the game, manager Roberto Martinez told the Liverpool Echo that there was little to worry about in regards to Stones' physical state, although he will be monitored over the coming days regardless.
"John was obviously more a precaution than anything," he said. "He had a little bit of a knock in his right knee and we couldn't take any risks.
"He will be assessed over the next 48 hours but I don't expect it to be anything too serious."
Stones has been a pivotal figure in Everton's positive start to the new campaign, while the fact that he remained at the club in the face of intense pressure from Chelsea - with the Daily Mirror among those to report on four failed bids - has made him an even more revered figure at Goodison Park.
The Toffees resume their Premier League campaign with a trip to take on West Bromwich Albion this weekend, where all being well, Stones will be fit enough to resume his outstanding individual impact in England's top flight.