Jason Day is trying to adjust his game to combat the pain that remains from his injured thumb and wrist.

Jason Day has resorted to changing his grip as he tries to battle through the heaviest schedule of the golf season.

Day lines up at the World Golf Championships Bridgestone Invitational at just 70 per cent, still hampered by pain through his left thumb and wrist and is obviously frustrated he can’t shake the injury.

The world No.9 is hopeful of contending at Firestone Country Club, but after experimenting with a tweaked grip the Queenslander will use the four rounds in the lucrative no-cut event more as preparation for the year’s final major in Louisville next week.

He has weakened his grip slightly to ensure his overlapping right hand pressure is more to the side of his left thumb knuckle, rather than pushing right down on top.

“I’m still trying to be able to practise fully. I’m getting in practise but not at 100 per cent and it’s just really really frustrating,” Day told AAP.

“I am trying to change my grip quickly and it feels awful right now, so I’m not to sure how I’m going to go this week.

“Normally I come in a lot more prepared, but it is what it is. When you have an injury you have to work around it.

“I’m just trying to see where the game is for next week. And try to work on the positioning of the hands to bring less pain.”

With little downtime in the golf schedule and with the US PGA tour playoffs coming after the PGA Championship, Day is unable to rest the injury significantly without shutting down his year.

As it stands surgery remains off the table.

“For a moment it seemed everything was good but now it’s come back a little bit and it’s just beyond annoying,” Day added.

“The unknown of when it will be ready is a big source of the frustration.

“But the good news is I had another MRI on Monday and it shows significant improvement from earlier in the year.”