I shot the Yankee game last saturday with the 135L lens. It was a night game. Yes the field was well lit, but I found a couple of issues.
1. at 800 most of the photos had noise in them, not bad, and I have not edited them yet, so I am not sure if the noise is completely removable. I was shooting at anywhere from f/3.5-f/8.
(Now this all may be my inexperience, so do not take it that the noise is an issue with the camera. I have learned that there is a lot to learn when using this camera)
2. One of the other issues was not the camera, but me. I would meter the image on a player's uniform (approximately 100ft -250ft from me), If the focal point left the uniform, the metering would drastically change. More than I was ready to handle as quickly as the action took place.
Also, I had a difficult time keeping the blurries away without being at 200-320 shutter speed. There were a couple at 125 that worked, but that was hit or miss, mostly miss. For the action shots, it had to be 500...which really put me in a funk-metering wise.
Metering on the grass/infield dirt/ uniforms/crowd were all very different, and different at different parts of the stadium. This is not the type of photography I have worked with before, and if I do it again (it looks like I have tickets to a few more games), I will need lots of help.
*I did take one photo I really liked. Jeter, Teixeira, Arod, and Cano were all discussing a play during the TV time out. I took many photos, and 2 were pretty good.