The league took on a number of changes for the 2015 season to increase its competitiveness. The number of clubs was reduced from 12 to 10, with the withdrawal of Tanjong Pagar United due to financial problems, and the merger of Woodlands Wellington and Hougang United. The league returned to a three-round format used from 2001 to 2011. The foreign player quota remained at five per club, but incentives were given to those who signed an under-21 player. The passing time for the mandatory 2.4 km fitness test was lowered from 10 mins to 9 mins 45 s. A new rule on age restrictions – a maximum of five players aged 30 and above and a minimum of three under-25 players for clubs with a 22-man squad, a maximum of four players aged 30 and above and a minimum of two under-25 players for clubs with a 20-man squad – was later reversed.