Knee Pain

Can anyone shed some light on this for me. I’m treating a patient at the moment for Patellar femoral syndrome but I’m not certain whether it’s true patellar femoral syndrome as he is only experiencing pain when he initailly weight bears on thr affected leg. He gets a sharp pain into the medial aspect of his patella but then the pain goes. He also experienes the pain when he weight bears on the leg to lift himself up into his van….. Can anyone give me a second opinion. He’s a semi-prof soccer player and is wanted back in the team as soon as possible. Thanks