West Indies captain Dwayne Bravo won the toss and elected to field against Pakistan in the third one-day international on Friday.
West Indies kept faith in the same playing 11 which leveled the five-match series at Guyana last Tuesday by winning the second
ODI by 37 runs.
Pakistan won the first match by 126 runs after Shahid Afridi took 7-12 and the home team was bowled out for 98.
Pakistan awarded an ODI cap to 24-year-old Haris Sohail, the left-handed batsman who replaced Asad Ali. Left-arm fast bowler Junaid Khan will be playing his first match instead of seamer Asad Ali, who could get only one wicket in the first two games at Guyana.
Pakistan has not lost against West Indies in its four matches at St. Lucia.
Pakistan: Misbah-ul-Haq (captain), Nasir Jamshed, Ahmed Shehzad, Mohammad Hafeez, Haris Sohail, Umar Akmal, Shahid Afridi, Wahab Riaz, Junaid Khan, Saeed Ajmal, Mohammad Irfan.
West Indies: Dwayne Bravo (captain), Johnson Charles, Chris Gayle, Darren Bravo, Lendl Simmons, Marlon Samuels, Kieron Pollard, Darren Sammy, Kemar Roach, Sunil Narine, Jason Holder.