Ben Spies is expected to announce a switch to the World Superbike Championship in 2009 after revealing he will leave both the AMA Superbike series and Suzuki.

Spies rode in what could be his final AMA race at the weekend, concluding the season with a record 95 point victory margin at Laguna Seca.

Spies ends his AMA tenure with three consecutive titles to become only the fourth rider to ever complete that feat. A total of 28 Superbike wins, including ten in 2008 alone, puts him third on the all-time winners list, while his 90 per cent career podium rate signals a remarkable amount of consistency.

"After racing in this series for four years and getting the best of Mat [Mladin] three times I was feeling a lot of emotions out there," he said. "I don't think we've had a DNF in my AMA Superbike career and that's because of a great crew I had behind me the whole time. It's been a great AMA career for me, now I'm looking forward to moving on to the next level in competition."

After good showings with the Rizla Suzuki team at Donington Park, Laguna Seca and Indianapolis, Spies was expecting to graduate to MotoGP in 2009, but lost out on a GSV-R seat when Rizla re-signed Chris Vermeulen and Loris Capirossi. As such, Spies has decided to sever his ties with the Japanese marque.

"Racing with Suzuki has also been amazing for me," he added. "They consistently gave me a great motorcycle and the opportunity they provided me to race in MotoGP helped give my career a major boost. All the great people I've worked with too, I can't thank them enough. And the fans that have supported me throughout my racing career over here are really special. That kind of backing is something I appreciate every day."

A rumoured move to JiR Honda came to nothing when HRC refused to supply the team with machinery and Spies now looks set to join the World Superbike Championship instead.

Rumours of a deal with the Yamaha Italia team to partner Tom Sykes have gathered pace in recent weeks, with SpeedTV reporting that he was spotted visiting their factory earlier this week.

If Spies is confirmed with Yamaha, he will be the first American to ride a factory Superbike machine since Colin Edwards back in 2002.

An official announcement from Spies is expected to be made later this week.