I feel fairly informed about PEDs in the track world, from friends and teammates who doped. But yes, I dont have personal experience in doping in the ball sports.
To the person claiming that NFL quarterbacks are throwing hard all the time, go back and watch some replays. They almost never throw hard in games. The long down field pass isnt completely gone, but it certainly isnt the mainstay it once was.
The average pass now is well under 10 yards in the air. Some starting quarterbacks last year had average in air passes of only 7 or 8 yards. It's all about quick short passes and snap decisions. They're not weak throws, but throwing too hard for short passes means the receivers drop a higher percentage. They're trying to strike a balance between throwing hard to get it through a narrow lane and throwing it soft so it's a high percentage catch.
Look at the injuries most quarterbacks sustain. It's almost never related to the muscles in the shoulder, which you would expect if it was highly taxing and PEDs and harder throws would help. It's almost always injuries due to contact (bruised ribs, finger strains) or stepping awkwardly (ankle, knee injuries). The shoulder injuries are almost always due to long term abuse, rotator cuff issues, tendonitis, etc.
Being an NFL quarterback is taxing, but more to your body in general than to just the shoulder in the way it is for an MLB pitcher.
Go look up stats if you dont believe me.