Is it the foregrip or butt grip or both? Mightn'd be worth the cost as a hypalon/evalon ie foam foregrip requires all the runners removed and rewrapped. the butt grip may be difficult from the butt end but this depends on the taper of the rod blank. Remember the reel seat is glued and is assumed not to be moved during this process. An alternative method is to tape on something like bicycle handlebar tape as this is typically the same kind of foam. I've used this on one of my 10 ft rods and it's come up a treat. You can get it in a variety of colours and while buying here may set you back around $30 or $40 on ebay it's less than $5 which is what I paid and I only used one. 

Thanks kknik i'lltry the gip for the bike first. Lots of cool colours on ebay.

heat shrink sleeves that work well. good idea is to use some 24hr glue under it before you shrink it