That was my thought, sprained something hopping down off the perch. He was fine the night before.
		
		
	 
You are correct in your assessment. I've dealt with leg issues quite a few times in hens and roosters.
I watched the video and I can tell you that he has severely strained or pulled a ligament or tendon. This will require long term placement in a cage for a long term healing process that may take several weeks or months. I've had good success with hens, but not so good with roosters. As a matter of fact I've ended up having to cull roosters because they dont like being caged AWAY from THEIR hens or even CAGED with THEIR hens. They are too active while caged when needing rest and relaxation while caged in order for the leg to properly heal. Their continuous movement and excitement while caged prevents proper healing and causes more severe injury.
However if you wish, you can try caging him away from the flock/out of sight of the flock, provide feed and water. Add vitamin B complex to his feed. Crush a few tablets into powder and sprinkle it on top of his feed to eat. It may or may not help speed up the healing process. 
After one week of being caged, remove him and see if there's improvement. If not, recage him for 10 days and continue with the vitamin B complex in his feed. After 10 days, remove him from the cage and see if there's improvement. If not, recage him and stop the vitamin B complex.
Time is the only thing that will heal these type of injuries. Like I mentioned, it can take weeks or months. 
Even if you see some improvement when he walks after being caged, but he still limps even just a little, recage him until fully healed. If you dont, I promise you he will severely reinjure his leg and you'll be back to square one and there may be permanent damage.
Remember, time heals. You have to be patient, but he wont be because it's his nature to be with his girls. Then eventually you're going to have to make a tough decision to let him continue suffering or end his suffering. 
Consider lowering roosts to prevent these types of injuries and eliminate other high places where birds can jump down from.
BTW: We just moved from westside Jax to Glen St Mary a month ago, love it here.