Spach injured his right knee Saturday while blocking in the second half of a 33-13 victory over Carolina.
"Stephen Spach has an ACL, so he's going to be done for the season for us," Arizona Coach Ken Whisenhunt said in his Monday press conference. "That is unfortunate, because he's been playing pretty good football for us."
The injury leaves the team with two tight ends on its roster -- Leonard Pope and Ben Patrick. Pope has been hampered by a sore ankle while Patrick has been struggling with an ongoing knee injury.
Whisenhunt also said he is unsure whether Pro Bowl wide receiver Anquan Boldin, who sat out against Carolina with a strained left hamstring, will be able play in Sunday's NFC Championship game against the Philadelphia Eagles.