When I was watching the Sox/Rays on TBS and there was a runner on 1st, they would show a < 9 > under his feet. What did that mean? I believe it was different runners and they did it for both teams.
It represents a 9-foot lead off first. I think that is considered average for a base stealer. So if the lead is toward the green side (over 9 feet), the runner is in better position to steal second. If he's closer to the red side, he's probably not going.
I think they're trying to show if the runner has a larger than normal lead off first. Not a bad idea, but people who watch a ton of games probably know a big lead when they see it without the graphic.