Casey having his 5th qualifying in a row at Laguna Seca, while Dani withdraws

Stoner: the fastest qualifying time of 1min 20.700sec.

The 29-year-old seven-times world champion joined Yamaha in 2004 and has won two titles with them, as well as 32 races in the top category. Yamaha said he would continue to be partnered by Spaniard Jorge Lorenzo in 2009.

Rossi who currently leads the overall standings, was second quickest in 1:21.147, and Nicky Hayden was third-fastest with a time of 1:21.430.

Dani Pedrosa, second in the overall standings, withdrew from qualifying and Sunday's race as he nurses a broken wrist and injured ankle in a fall at the German Grand Prix.

The Honda driver had hoped his injuries would allow him to compete, and he completed both of Friday's free practice sessions before throwing in the towel.

Stoner will be going for his fourth straight victory from pole as he battles to narrow the gap on Rossi in the championship race.

Rossi, the only other rider to take five straight pole positions, leads Pedrosa by 16 points while Stoner is four points adrift of the Spaniard.

Jorge Lorenzo, James Toseland and Randy de Puniet will start from the second row.