  We prove an $\varepsilon$-regularity result for a wide class of parabolic
systems $$ u_t-\text{div}\big(|\nabla u|^{p-2}\nabla u) = B(u, \nabla u) $$
with the right hand side $B$ growing like $|\nabla u|^p$. It is assumed that
the solution $u(t,\cdot)$ is uniformly small in the space of functions of
bounded mean oscillation. The crucial tool is provided by a sharp nonlinear
version of the Gagliardo-Nirenberg inequality which has been used earlier in an
elliptic context by T. Rivi\`ere and the last named author.
