Looking at the stats, this does seem to be a 3rd innings issue. In the last 3 years Anderson averages 25 in the 4th innings, and he averages 13 this year, it's just that he has only bowled 21 4th innings overs this year, compared to 102 in the 3rd innings.
If you limit the analysis to 3rd innings', particularly if you remove the game where England enforced the follow-on (he got 2/45), it starts to look really bad. In the last 3 years in non-following-on 3rd innings he has bowled 142 overs and taken 3 wickets at an average of 128, with never more than 1 wicket in an innings.
Over the previous 3 years in non-following-on 3rd innings he bowled 230 overs and took 33 wickets at 15, his best average and strike rate.
Looking at the stats, this does seem to be a 3rd innings issue. In the last 3 years Anderson averages 25 in the 4th innings, and he averages 13 this year, it's just that he has only bowled 21 4th innings overs this year, compared to 102 in the 3rd innings.
If you limit the analysis to 3rd innings', particularly if you remove the game where England enforced the follow-on (he got 2/45), it starts to look really bad. In the last 3 years in non-following-on 3rd innings he has bowled 142 overs and taken 3 wickets at an average of 128, with never more than 1 wicket in an innings.
Over the previous 3 years in non-following-on 3rd innings he bowled 230 overs and took 33 wickets at 15, his best average and strike rate.