One of the most common objections raised when someone suggests that Ricardo Allen has a real shot at the starting free safety job has to do with his height. "He's too short," is the frequent retort, and while that's an understandable sentiment, it's also a wrong one.
Earl Thomas, considered by many to be one of the finest safeties playing today, stands just 5'10". Ricardo Allen's just an inch shorter than that, and if he plays quality, aggressive football, that single inch isn't going to kill him. Even if he's unlikely to ever become Earl Thomas.