marks on the rubber

hi

 you know when you serve you loosen you grip , my rubber has a mark there and on where my forefinger goes. my coach says that i hold my bat too tight and he has never had that problem, but when i serve i try to hold it as loose as i can and of i hold it any looser my bats going to fly out of my hand. do you have marks on your rubbers or do i hold it too tight 

thanks:) 

Hi Jimmy,

If there are marks on the rubber just from the serving hold it is probably OK depending on how old your rubber is.

Even though you are holding the fingers loosely, you have quite a good hold where your knuckle and thumb are holding on to the bat.  This could cause enough friction to wear the rubber down after a while.