Size Difference Is Too Much
In his battle with Nate Diaz at UFC 202, McGregor was overwhelmed by the sheer size of the Stockton, CA native despite weighing-in near or at the 170-lb. limit. Of course the longer McGregor stays at this weight, the more he gets accustomed to the added bulk.
But despite the fact, McGregor is just naturally built as a small fighter. Head coach John Kavanagh has reiterated that it would be no issue for McGregor to make the UFC’s 145-lb featherweight limit and that it would actually be quite easy for him to do so.
This would put McGregor at a size disadvantage every time he steps into the Octagon with a true welterweight. GSP is one such guy and has campaigned most of his career in the division.
A very strong wrestler who knows how to use leverage and body weight to control guys on the ground, GSP also owns one of the most impressive takedown success rates in the entire fight game bar none.
The fact that he’s naturally bigger than McGregor just works to his advantage. Diaz was already too big for McGregor, but a real welterweight like GSP would absolutely dwarf him.