I do not know from a food safety point of view. But, from a horticultural point of view, as vegetative matter decays, or for that matter, ripens, it out gasses as the cells break down. For the price of cabbage, toss and buy seems a good idea.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."