The Silkmen have lost their last five League Two games, slipping to within seven points of the relegation zone against the backdrop of a crowded treatment room.
"No, I've not seen anything like this during my time in the game," said Simpson.
"We've got seven or eight frontline first-team players out. We beat AFC Wimbledon 4-0 at home at the beginning of the season and I think there were only three or four of those players playing when we lost there last month. So it just shows you how many players we've had out."
He added: "To be fair to us we probably haven't picked the points up that our performances have deserved of late - we've just fallen a little bit short.
"Every performance they've given me I couldn't really complain about. I can't fault the performances, it's just the results have been poor."
Macclesfield host second-from-bottom Plymouth Argyle on Saturday, with seven points separating the clubs in the table.
