Advice needed. A journal cap came off!

Think I agree with caferacerx. If you reinstall the cap with a new bearing, your motor will tell you pretty quickly if it's liking the new arrangement. If it works -- cool. If not -- then you'll have to face the inevitable and turn the crank, replace the cap and have it line bored. Might as well do all the bearings at that time and freshen up the cylinders.