The midfielder has been ruled out for the rest of the tournament following his injury against Indonesia
Hariss' injury follows that of Shaiful Esah who had to be replaced in almost similar circumstances against Malaysia in the opening match on November 25.
Despite making his international debut at the age of 15, the 22-year-old made his first appearance at the biennial AFF Championship against holders Malaysia on Sunday. Hariss had missed previous editions due to injuries and it appears the midfielder has been struck down once more.
Besides Shaiful and Hariss, the Lions will be without the suspended Irwan Shah as well on Saturday as they go into their crucial encounter with Laos.
Singapore defender Baihakki Khaizan took to Twitter to share his sympathy for his team-mate, tweeting: "Felt terrible for Harris Harun who suffered from a fractured fibula (shin) stay strong bro.'