Cap 7-12 cm broad, convex, expanding to nearly plane, in age sometimes plano-concave; margin at first incurved, then decurved, often wavy, seldom striate, occasionally raised in old specimens; surface subviscid when moist, otherwise dry, glabrous, color when young, whitish to dingy-cream with vinaceous tints, in age overlaid with brown to grey-brown pigments, vinaceous tones usually still evident; context white, firm, 1-2 cm thick, slowly and erratically changing to pale vinaceous-buff (most consistently just below the cuticle), eventually grey-brown, not turning black; odor at first mild, unpleasant at maturity; taste mild.
Gills adnate to adnexed, becoming subdecurrent to decurrent, brittle, relatively narrow, close to subdistant, color when young, off-white, becoming dingy-cream, bruising vinaceous-pink to rusty-brown, especially the edges, not turning black.
Stipe 2-7.5 cm long, 2.5-3.5 cm thick, central to occasionally eccentric in cap attachment, usually solid, equal to narrowed slightly at the base; surface typically glabrous, at first pallid to cream-buff, in age dingy pinkish-brown, vinaceous-brown or grey-brown; context firm, brittle, with similar color changes as that of the cap; veil absent.
Spores 7.5-10 x 6.5-7 µm, subglobose to ovoid; ornamentation amyloid consisting of low warts and thin lines, sometimes forming an inconspicuous reticulum; spore print white.
Solitary or in small groups in mixed woods, probably associated with oaks; fruiting shortly after the fall rains.
Russula eccentrica is one of several dingy Russulas that redden or blacken with handling or in age. These include Russula densifolia, R. nigricans and R. dissimulans, whose tissues bruise reddish, then go grey to black, and Russula albonigra and R. atrata that blacken directly without an intermediate reddish stage. Russula eccentrica is distinct from all of the above in that its cap and gill tissue only redden, sometimes darkening to red-brown or grey-brown, but never to black. It should be noted that these color changes occur slowly sometimes taking up to 15 minutes to a half hour. The species name refers to the stipe attachment which is sometimes, but not consistently off-centered. Russula eccentrica often fruits close to yellow chanterelles, and is used by some collectors as an indicator species, much like Amanita muscaria is with Boletus edulis.