The 29-year-old spin wizard will be joined by another as yet unnamed Pakistani Test player for the One day competition, which will be played under a league format this year.
Saqlain, whose county career at Surrey ended after eight years in 2005 following a knee operation, played 49 Test matches and 169 one-day internationals, including two World Cups.
His career in one-dayers for Pakistan lasted a decade from 1995, and he took 288 wickets.
The right-arm off-break bowler had his finest season in 2003 when he was the fastest bowler to reach 100 one-day wickets.
He also belongs to an elite category of spin bowlers who have claimed hat-tricks in One-day cricket on not one, but two occasions - both against Zimbabwe.