Idea for summoner spell cooldowns

I thought of an easier way to track your enemy's summoner spell cooldowns. I think that it would be pretty cool if when you see an enemy use you could press tab and click on their and it will start counting down until it comes back up. This is a way better alternative to just calling the time in chat because you might not remember but if you don't know when the enemy has you can just press tab and look at how much time is left on it.

This won't be exact but I think it it would still be nice.

I've included an awful picture I edited to show what it could look like.