All my woven white shorts (Nadal, Delpo shorts) get dingy after a few months of use. But the blue-tinge might be your detergent or something.
It's like a white over-grip. It'll just get more off white the longer you use it.
Yonex EZONE Ai98 w/ PolyTour Spin x Volkl Cylcone 18 at 45 lbs