The 30-year old striker, fresh off a 2012 campaign which yielded 27 league goals and the MLS MVP, is likely to become the Quakes only Designated Player with the revised deal.
"We are in the process of working something out," Wondolowski told Sporting News.
"It hasn't quite happened, but it should be done, if everything goes smoothly, in the next week or two. As long as everything goes to plan, before the season."
Wondolowski is San Jose's all-time leading goalscorer with 65 league goals from just over 100 appearances and has been named in the MLS Best XI in each of the past three seasons.