Start watching the attached video from 8:20.
The last two minutes are dedicated to adding circles in Premiere Pro. Looks to be CS3 or CS4.
In part 2 of this podcast, host Jeff Schell shows you how to take a clip of a football game -- or any sports event -- and export a frame of video to Adobe Photoshop in order to create ESPN-style visual effects, such as having two players briefly grow and shrink on the screen to highlight them.
Finally, Jeff adds a simple Premiere Pro title containing two circle objects to help make the desired players stand out.
(Note: Their site is SLLLOOOOWWWWW. That's why I just attached the MP4 for you here.)
Learning how to import video to Premiere is somewhat basic, fairly easy.
Learning how to add circles is rather easy, too.
Motion tracking takes more effort, but can be done.
There's some REALLY lousy motion tracking video tutorials on Youtube. Lots of rambling, and quality isn't really as good as it should be for a small screen size. If you want a good video on this, let me know. I can either find one from a pro, or possibly try and make one myself.