Nothing, but he balances out the team.
Just like for months so many were complaining about Hafeez and what he brought to the side, the same should eventually turn out with Tanvir if he can gain some consistency and confidence through match play.
You need an opening bowler who doesn't do the same redundant things other bowlers do. I mean if PP'ers had their way, we'd have 4 fast bowlers bowling 95 mph for 40 overs of the game. What good teams have is a variety of bowlers to use.
Tanvir is no match winner, but he brings a bowling style that compliments our quicker attacking bowlers. We have plenty of them in Gul, Akhtar, Riaz.
Truth is, if not for Amir being suspended, Tanvir would not be needed. Since Amir is out, we have to replace him. I don't see a better left handed option with experience at the national level. Junaid Khan hasn't played a game and obviously didn't impress the coaching staff enough to get even 1 game when he was with the team. For now, Tanvir was the best choice to replace Amir's spot.
I mean not like our bowling has been weak in either game. 3 wickets for him in 17 overs of play. Shoaib has gone wicket less in 4 overs being smacked around. Razzaq hasn't taken a wicket in 2 games. I mean, say what you want about Tanvir, but he's a decent bowler who seems to be able to take wickets. I rate him behind Gul, Riaz and Akhtar, but he compliments Gul and Riaz more than an Akhtar would. Plus he can hit the bat a bit.
Only reason I want to drop him is atrocious fielding.
I'd combine our specialist bowlers as follows.
Lineup 1: Gul, Tanvir, Riaz, Ajmal
Lineup 2: Akhtar, Tanvir, Gul, Rehman
Lineup 3: Akhtar, Tanvir, Riaz, Ajmal
When you pick a team you have to think about the entire team and not just individual talent. Tanvir is far less of an individual talent than Shoaib Akhtar, but thus far I see him compliment our team well. He hasn't even played international cricket at this format for 2 years. In 2 matches, 3 wickets and less than 6 runs an over. I'm not saying he's great, but he certainly isn't awful either.