Hendricks best chance to win this fight is to take a Chael Sonnen approach, and pressure GSP. Try to take him down instead of constantly defending takedowns. I've lost count of how many of GSP's opponents wait for him, and constantly defend tds, jabs, etc... If Johny Hendricks comes out as the aggressor and goes for broke to finish, he will probably win. If he shows up with the same gameplan as GSP last few opponents, standing/ waiting/ and relying on his exceptional wrestling background back him in defending GSP's shots, he will get taken down, and dominated for 5 rds.
Matt Serra and Chael Sonnen. The only two fighters smart enough to pressure the fastest fighters in mma.