You need to decide the focal length first. You could carry a 70-300 mm lens round the pitch and you could use it for handheld pictures (a rough and ready rule is that the shutter speed should be faster than the focal length so, if the zoom is on 250mm, the shutter speed should be faster than 1/250th second to give a handheld picture a decent chance of coming out right) or with a monopod. A 650-2600 mm zoom is going to be too big to carry around following the action in my opinion and is more suited to being set up in one place so that the higher magnification, in effect, does the walking.
Some pros will have several cameras with a range of lenses so that, as the action moves nearer or further away, they can simply put one down and pick another up without having to waste seconds swapping lenses. Pros will also spend more to get the best quality optics and the widest aperture to give themselves the best chance of not missing a picture. There is almost no limit to the amount of money that could be spent.
As you've already got a 28-200mm lens, my advice would be to next get something that works mostly outside that range. Perhaps a 300mm telephoto or a 150-500mm zoom. I feel that there is too much overlap between a 28-200 lens and a 70-300 one unless you can justify the purchase on other grounds.
There is nothing wrong with Sigma, Tamron and Vivitar lenses. They have all been around long enough to know how to make lenses. Unless you can see any obvious limitations with them, you should spend the money and give one a try. A Nikon made lens will be better quality but at a much higher price.
It's not worth buying from an overseas seller though, in my view. At best you will get a VAT/duty/fees bill when it arrives if it is coming from outside the EU and returns will be difficult if there is a problem. Like any other expensive item, there are cheap imitations and fakes around.