Clearly underexposed. Did you use the camera's meter or an external one. That's a difficult shot and still freeze motion. I own a D7000 but still do not remember the upper limit of the ISO. If possible, push the ISO and try matrix metering instead of manual. In sports photography, it seems to me that manual mode would be difficult and still get the "money shots."

Since the lighting is static (doesn't change except for the shadows) you could take some test shots and then just leave the settings there. However, if you take shots in the shadows you will have to compensate. You can use the EV bias to correct for shadows - just know that the shutter speed will likely be slower than you would like. So, stay away from shadows shots and use the higher light levels where the action is likely to be anyway.

Does the sports arena forbid flash photography? That would work for close action but not telephoto shots

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What mode are you shooting in? If you are shooting entirely in Manual including actually setting the ISO, I don't think the +3 exposure compensation will do anything. I would suggest trying full Manual and set your shutter speed to whatever you need to stop blur, and your aperture at the 2.8 in this situation and try putting the ISO in Auto. If this gives you too dark an image check what you have the max ISO set to in the auto ISO menu. I have and use a D7100 but I am not familiar with the lens you are using. If it has vibration reduction on it, make sure it is on and you may be able to lower the shutter speed some if necessary.

So the reason you are underexposed is you are relying on the auto ISO and the center weighted metering. The auto iso is maxxing out at 5000 so it can't give any more, so your exposure compensation has no impact because it doesn't have any more ISO to give, and the center weighted metering, if confronted with a relatively bright area like a white shirt or the bright walls tries to tell the camera to darken. Matrix metering is superior when subjects are moving around and you don't have time to think the exposure through.

So I would up the auto ISO to the max 'native' value, I think you get 6400, or better yet go to full manual with the iso at 6400 and switch to matrix metering. Keep the lens wide open and use the fastest shutter speed the light will allow.

So the reason you are underexposed is you are relying on the auto ISO and the center weighted metering. The auto iso is maxxing out at 5000 so it can't give any more, so your exposure compensation has no impact because it doesn't have any more ISO to give, and the center weighted metering, if confronted with a relatively bright area like a white shirt or the bright walls tries to tell the camera to darken. Matrix metering is superior when subjects are moving around and you don't have time to think the exposure through.

So I would up the auto ISO to the max 'native' value, I think you get 6400, or better yet go to full manual with the iso at 6400 and switch to matrix metering. Keep the lens wide open and use the fastest shutter speed the light will allow.

Wow, I'd say about the only camera adjustment I might make is shutter speed - slow it down a tad - but you run the risk of a slightly blurry image of the player. Shooting RAW would give you some latitude in exposure adjustments. I spend a few minutes using Adobe Camera Raw in adjusting the exposure and it did make an improvement in the image even tho its a JPG. With the image in RAW format I think there is a bit more that can be done to improve the image - noise isn't bad and can be dealt with reasonably well.