I'd probably use Motion for something like this. You can use Final CUt if you want, and keyframe it, but it depends on how you want the arrow to interact with the player.
You will need to draw an arrow, or find an arrow from somewhere. Set it to have a transparent background either through masking or alpha/luma channels on background colour (if it has a plain background). Composite that over the playing footage, orientate it so the arrow is displayed on screen as you want it, and then keyframe it's movement to follow the player.
There is some software called game breaker, expensive, but it's what the sports channels use a lot of the time. You know, where they have football or rugby footage and they circle a player and draw arrows over it. It's also used as a training aid because you can index the footage on the fly for anything such as fouls, tries, goals, scrums... whatever you want, and then at the end of the match when analyzing the footage, you can zip through all the tries, all the goals etc at the touch of a button.