It happened around 4:45 Sunday afternoon.
Authorities say Detective Michael Braxton was travelling inbound on Route 40 when another car changed lanes into his path.
The officer was able to avoid striking the car but the result threw him off his motorcycle and into a street sign.
Braxton suffered a leg injury and was taken to AtlantiCare Regional Medical Center.
At the time of the crash, Det. Braxton was travelling with several friends, including other Atlantic City police officers.
The other driver did stop at the scene.