To be fair, that article mentions that Ki is now playing a bit further forward, but he certainly can play the Liam role. Also, I expect Sunderland have limited funds, by Prem standards, so may not be able to buy both?
Thought this was interesting:
http://uk.eurosport.yahoo.com/news/football-poyet-planning-ki-persuasion-083942534--sow.html?utm_source=twitterfeed&utm_medium=twitter