Contract years are typically where a players numbers blow up, inflating his value before he potentially hits the open market. Given their plans to wait until season's end to negotiate an extension with Sandoval, the Giants certainly wouldn't mind a career year from the Panda to additionally bolster an already upgraded offense.
Surprisingly, what they've received thus far is the polar opposite. Despite some flashes of the old Panda, he's been nothing short of a burden with the bat in his hand. Of all MLB third basemen to have received at least 50 plate appearances thus far, Sandoval ranks dead last (out of 40) in pretty much every category. He's not hitting for power, he's not getting on base, and he's still swinging at garbage pitches - the latter now slightly magnified given it's not resulting in the success that it has in the past.