I think the genus is Hogna.

To be honest, its really hard to tell any good diagnostic characteristics from this picture, however, of the 3 known species of Hogna (radiata, graeca, effera) none quite correspond with this spider, so this is either
A: a Hogna that has lost most of its hairs due to weathering or
B: some weird Alopecosa (hard to tell which due to the large number of species)
unfortunately the two Generas have some surprisingly similar looking spiders and to be sure we'd have to look at genitals or the number of teeth in the Cheliceral retromargin.