The identification of type Ib/c supernovae as GRB progenitors is motivated by the association of GRB980425 with SN1998bw and of GRB030329 with SN2003dh .
While the \gamma -ray luminosity of GRB030329 was typical to cosmological GRBs , the luminosity of the nearby ( 40 Mpc ) GRB980425 was \sim 5 orders of magnitude lower .
The large luminosity difference is commonly explained by hypothesizing that either SNe Ib/c produce two different classes of GRBs , or that GRB980425 was a typical cosmological GRB jet viewed off-axis .
In the latter scenario , strong radio emission , L _ { \nu } \sim 10 ^ { 30 } \nu _ { 10 GHz } ^ { -1 / 2 } { erg / s Hz } , is expected at \sim 1 yr delay due to jet deceleration to sub-relativistic speed , as observed from GRB970508 .
The radio luminosity of SN1998bw was 3 orders of magnitude lower than this value .
We show that the low radio flux may be consistent with the off-axis jet interpretation , if the density of the wind surrounding the progenitor is lower than typically expected , \dot { m } \equiv ( \dot { M } / 10 ^ { -5 } M _ { \odot } { yr } ^ { -1 } ) / ( v _ { w } / 10 ^ { 3 } { km% s ^ { -1 } } ) \simeq 0.1 instead of \dot { m } \gtrsim 1 .
The lower value of \dot { m } is consistent with the observed radio emission from the supernova shock driven into the wind .
This interpretation predicts transition to sub-relativistic expansion at \sim 10 yr delay , with current \approx 1 mJy 10 GHz flux and m _ { V } \approx 23 optical flux , and with \approx 10 mas angular source size .
It also implies that in order to search for the signature of off-axis GRBs associated with nearby Ib/c supernovae , follow up observations should be carried on a multi-yr time scale .