Following shortly after the announcement earlier this week that that Temasek Holdings are to invest a significant eight-figure sum into ONE Championship, sources close to the promotion have revealed they have initiated talks with the hottest free agent in MMA today--Rory MacDonald.Confirmation of ONE Championship's interest in MacDonald comes just 24-hours after it was reported by Chamatkar Sandhu that Bellator MMA had also established a line of communication with the former UFC welterweight title contender.MacDonald is testing the free agency market having told MMAFighting "now it's all about making money" and that the next contract he signs will be with "whoever wants to pay me the most."If MacDonald was to join ONE Championship, he would likely be competing in their welterweight division where American Ben Askren is currently the champion. No doubt, a dream fight between Askren and MacDonald would be one of the biggest fights in ONE Championship history and would create attention for the promotion with eyeballs from both East and Western markets.Outside of a big money fight with Askren, other stars in the ONE Championship welterweight division include Luis Santos, Nikolay Aleksakhin, Ariel Sexton, Rafael Silva and Roger Huerta.MacDonald, who is ranked as the number #2 best welterweight in the world, is currently riding a two-fight losing streak having lost to Robbie Lawler in the 'Fight Of The Year 2015' at UFC 189, and last month at UFC Fight Night Ottawa to Stephen Thompson.For the minute, MMA's hottest free agent remains unsigned. Unsurprisingly, MacDonald isn't going to be short of options.