Zaheer, 27, dropped from the Indian team after the recent Pakistan tour, will step in for Bracken, who has earned a regular place in the national squad, the county said on Monday.
"I'm delighted to be playing a full season," Zaheer told Reuters. "Seniors in the team have been advising me to play county cricket.
"It will help me develop as a bowler and stay match-fit."
Zaheer has played 42 Tests and 107 one-dayers.
