Akhtar appeared to be injured during Monday's fourth ODI at Lord's, and concerns were raised about his participation in the final game.
"Shoaib Akhtar will play in Wednesday's decider at the Rose Bowl. He is not injured, and is fit to play," PakPassion.net quoted Saeed, as saying.
Pakistan has leveled the five-match series at 2-2 with a 38-run victory in the fourth ODI.
The 35-year-old has taken 232 ODI wickets in his 151 appearances for Pakistan at an impressive average of 24.2.