No he left the team because he is absolute shitt at any real form of cricket. He even said so himself.
Afraidi? Shitt at any real form of cricket?!?
Tests : 27
Runs : 1716
Ave : 36.51
HS : 156
100 : x5
Wkts : 48
Ave : 35.60
SR : 66.54
BB : 5/52
Hardly 'shitt', maybe not a perfect batting average but as all-rounders go I think most would take those figures, even Australia. Half his innings have been opening (892 runs @ 37.17) and the other half batting six or below (824 runs @ 35.83)
His bowling hasn't really been used that much, I guess with the presence of Kaneria and Mushtaqs Saqlain and even Ahmed it was never likely to be, but here is an interesting split.
Shahid Afridi Test bowling
Tests 01-11 (98/99-00/01) : 11 Tests, 20 wkts @ 29.20 (SR 59.35)
Tests 12-15 (01/02-04/05) : 4 Tests, 1 wkt @ 192.00 (SR 318.00)
Tests 16-27 (04/05-10/11) : 12 Tests, 27 wkts @ 34.56 (SR 62.56)
Both Mushtaq Ahmed and Saqlain Mushtaq bowled up to 03/04, Danish Kaneria from 00/01 to 10/11, hence why Afridi hasn't the volume of wickets you might expect from an all-rounder.