South Korean star Inbee Park, who leads the money list and player of the year rankings, is sitting out the tournament as is Suzann Pettersen of Norway, who trails Park on both lists.
Lewis leads the LPGA Tour in top-10 finishes this season with 16. Her three victories this season include a major championship, and she still has a remote shot at winning the player of the year award with three events remaining.
Karrie Webb of Australia, who won here in 2006, was tied for 36th place after an even-par 72.
The 54-hole Mizuno Classic is made up of 43 LPGA Tour players and 35 members of the LPGA of Japan.