Silva was captain of Panadura Cricket Club against Kalutara Physical Culture Club in January that saw 587 runs being scored on the final day despite only 180 being scored over the first two days.
The SLC said in a statement: “Please note that the two teams have been found guilty of misconduct and not playing to the spirit of the game, and not of match fixing.”
The now 37-year-old Silva played 11 Tests, 75 ODIs and 16 T20Is between 1999 and 2011 with his last appearance for Sri Lanka coming in a T20I against Pakistan in November 2011.
The ban for Silva was odd as he did not take part on the final day of the game in question, although he was in the team the first two days.
SLC vice president K Mathivanan told ESPNcricinfo: “[Silva] is the captain-cum-coach [of Panadura], so he’s responsible.
“For any team the captain is responsible. Whether he made the decision or not – we don’t know that part. But according to the ICC rules – even for slow over-rates – the captain is responsible.
“How do you know that he didn’t agree [to manipulate the result]? He could have come and given evidence in front of the independent committee [that had made the inquiry into the incident]. He never did.
“And also, each player had been represented by lawyers, including Chamara Silva. Lawyers appeared on behalf of all the club players.”