Former champion James Stewart is becoming frustrated with mid-season crashes in 2011.

Former dual AMA Supercross Champion James Stewart has rued a host of rookie errors in recent weeks, casting his AMA Supercross title chances in doubt as just five rounds remain in season 2011.

The San Manuel Yamaha rider again crashed on lap one at Toronto in Canada last weekend, before later clashing with former series leader Ryan Villopoto. From there Stewart rebounded to fourth, albeit disappointed that he was unable to take victory.

“I’m just making way too many mistakes,” admitted Stewart, whose DNF last week in Jacksonville was only the fifth time from 71 starts that he had finished outside of the top 10.

“I’m making it hard on myself, but in the end I wanted to be smart and take what I could get this week, so I didn’t push too hard to chase the guys up front.

“There are still five rounds left, and that’s a lot of racing.”

Stewart now sits fourth in the title chase, 20 points behind arch-rival and current title leader, Australia’s Chad Reed.