How do you think capping off back to back Open Championships with leading his side to another Ryder Cup victory would feel to Harrington? Pretty good I would think. He has had quite a run, and he has the game to keep it going.
Harrington is quite tall, but he tries to maintain a very compact swing. In the video below you can see him working on the range with a glove under his right armpit. He is working on keeping his right arm connected to his body during his backswing. He does not want any air to get into his armpit. By doing this his swing stays on line much easier. For taller players it is easy to get a little loose and have you arms fly away from you. He is practicing a great drill to avoid that problem.
If you make a backswing and stop at the top, your right elbow should be pointing towards the ground. If it is pointing anywhere towards the sky then you will probably see how your armpit has become exposed to air. I would highly recommend the drill Harrington is doing, and watching for this in his swing this weekend.