The best-of-three game series in Sri Lanka is locked at 1-1 after Pakistan won a nail-biting first game before the hosts cruised to victory in the second.
With everything to play for when the teams face off in Dambulla on Saturday, Pakistan have selected Ajmal despite the off-spinner being under scrutiny for a suspect action.
The 36-year-old returned from Australia where he had tests conducted on his action and has been rushed back into the side after being excluded from the opening two ODIs.
Pakistan officials fear Ajmal may be stopped from playing to work on his action, which could spell a period of up to two months on the sidelines.
Sri Lanka will hope the likes of captain Angelo Mathews and Thisara Perera can repeat their performances from the second game.
Mathews managed an impressive 93 with the bat while man-of-the-match Perera took three wickets to go with his 65 runs.
Pakistan will need to improve with the bat if they are to have any chance of replicating their last series in Sri Lanka which saw them return home victorious.
Ahmed Shehzad and Mohammad Hafeez were the only players to score more than 50 in the second ODI.
Wicketkeeper-batsman Umar Akmal will be particularly fired up to post a solid contribution with the bat after enduring a very disappointing return of just 16 runs in the first two games of the series.