If repair materials had been needed, they could have been sent on that mission...
They couldnt do the repair in space. There are no hand holds on the outside of the Shuttle so there is nothing to hold on to. They had no teether so a trip outside would have accomplished nothing but a sooner death. BTW, the Russian ship was in Kazakstan which would have taken at least a day to get the materials there minimum, assuming they were readily available in the US. Another day to catch up with the Shuttle. Then how do you offload the materials from the unmanned russian ship without a teether on board the Shuttle?