It's important to have a 5 man attack and one guy to come in and just bowl flat out for 3 4 over spells.So the plan was to select Haris on a condition that he will bowl only 10-15 overs in a day. Why Wahab wanted to select a bowler with this special limitation, who can't bowl as per the need of team? Haris should focus only on T20 leagues, no international cricket for him anymore
It's part of a top and well balanced attack.
Simon Jones and Mark Wood are 2 examples from England