Swann misjudged an attempted pull shot off Essex bowler Tymal Mills and was hit on the right forearm.
Chelmsford, England: England offspinner Graeme Swann has gone to hospital for an X-ray after being struck on the arm during a warm-up match against Essex, handing the team an injury scare ahead of the Ashes series against Australia.
Swann misjudged an attempted pull shot off Essex bowler Tymal Mills while batting for England on day two of the four-day match, and was hit on the right forearm.
Swann batted on, making 94, but didn't take the field following England's declaration on Monday.
The first Ashes Test starts July 10 at Trent Bridge, Nottingham.