"After reviewing my past couple of years' performances in red-ball cricket and the upcoming limited overs cricket, I have decided to take time off from first-class cricket," Riaz said in a statement released by the Pakistan Cricket Board (PCB) on Thursday.
He has conveyed his decision to the PCB while confirming that he has withdrawn from the upcoming Quaid-e-Azam Trophy, the first-class competition in Pakistan.
While has hasn't ruled out his return to red-ball cricket in the future, the left-armer stressed that he would do so only if he's convinced that that he can perform.
"During this period, I will like to focus on 50-over and 20-over cricket, and continue to assess my fitness for the longer version of the game. At a stage I feel I cannot only return but also perform with the red-ball, I would make myself available," he added.
The 34-year-old last made a Test appearance against Australia in October 2018. Having made his Test debut in 2010, Riaz has featured in 27 Tests for Pakistan, grabbing 83 wickets.