Why didn't Iannone renew his contract with Suzuki?

The maniac was performing relatively well from what I remember, he bagged a lot of podiums along with Rins. Why did Suzuki let him go to Aprilia for Mir?

The maniac was performing relatively well from what I remember, he bagged a lot of podiums along with Rins. Why did Suzuki let him go to Aprilia for Mir? http://ifttt.com/images/no_image_card.png