How to get rid of stomach fat?

Hi. I always have played soccer pretty much every single day for 4 years and am a very active person. I have always had quite a bit of fat stomach like rolls etc. but ever since my injury, I have gained so much more. I had collateral ligament damage on my knee and couldnt do any cardio exercise for 10 weeks, only weights for my upper body. I did ab workouts 3 times a week but nothing has worked and gained more fat. Any ideas on how to get a ripped and flat stomach?