I used to shoot using burst mode a good bit for football but do it more sparingly now. I will use it more near the goal line or on a long pass play but even then generally only shoot 3 to 6 shots at a time. You might think of shooting RAW+, at least at the beginning to see if the camera is keeping up, then you can see how the JPG works and still have the RAW shots for fixing when needed. I shoot mainly to create web galleries and get usable shots at ISOs up to even 6400 when necessary on the K5. I bought a Tamon 1.4x TC to use with my Tamron 70-200 and it does help get a little extra reach. Once the lights come on I usually take off the TC. I shoot TAv or Av most of the time but often switch to Manual mode when the lights come on and even use the 540 flash some. I am able to shoot right from the sideline so I can get pretty close. Did learn quickly that if the player is getting bigger in the view finder it might be time to move.
I've not taken a direct hit but have been brushed a time or two.