I regularly stand at Mid-off or Mid-on, and the fact is that you can hand the ball back to the bowler, so I am not certain why that would be a factor?

If he is bowling well, that's fine, but is he going to be a liability with the bat, or in the field? Is his bowling that much better than Lewis or Plunkett? If it isn't why risk it?

Scenario one - Anderson in the field at third man, NZ need two runs to win, last ball. The Kiwi batter flays at a wideish ball, it travels in the air to third man - Anderson, due to a broken finger spills the chance, and the batter cross for a second run.

Scenario two - England need four runs to win, with one wicket in hand and one ball left. Wicket has just fallen, and Anderson is strapped up, but in. Juicy half volley, but Anderson cannot get any power in the shot, he is a left hander when batting, the left (power hand) is the broken one and the ball gets about as far as cover-point...

Would it have been worth risking him? So it is more than just a matter of whether he is bowling well...