The 33-year-old joins on an emergency loan following an ankle injury to number one Tommy Lee and the former Coventry man will start against Preston in their semi-final second leg.
With keepers Aaron Chapman and Myles Wright also out injured, the Football League gave Chesterfield special dispensation to sign Murphy on loan.
“When we were looking for a keeper at short notice, Joe was an obvious choice,” boss Paul Cook told the club’s official website.
“He was coached by Eric Nixon as a youngster at Tranmere and has vast experience with over 500 senior appearances under his belt. I’d like to thank Huddersfield for helping out by loaning Joe to us.”