Could an abdominal strain from working out create a bruise?

Posted by BethC

My healthy 20 year old college son has a bruise on his upper abdomen, near his ribs. There is a slight pea sized "bump" within the bruise. He wasn't hit or otherwise injured, could he possibly have an abdominal strain (no pain except when touching the bruise) that is causing this? The bruise looks like a normal bruise purplish in color (4 days out from him first noticing it)