TAMPA, Fla. – The United Soccer League announced Wednesday a few new rules for the 2018 season.

These changes were vetted by the various competition subcommittees and approved by the full technical committee meeting at the annual meetings in Orlando earlier this month.

“We are pleased to continue the evolution of the USL’s rules to bring our league in line with top domestic and international competition, and offer greater roster flexibility to our clubs,” USL president Jake Edwards said in a statement. “The changes the league’s rules have undergone over recent seasons have occurred thanks to close collaboration with our clubs and will deliver the highest level of competition on the pitch for our fans.”

Among the changes:

* USL regular-season games will be considered official upon reaching the 70th minute of the match. Previous rules allowed games to be declared official after the completion of the first half. All games in the USL Cup Playoffs will continue to be played to conclusion.

* USL Cup Playoffs games will allow a fourth substitute to be used in extratime. The fourth substitution must occur prior to the final whistle in extratime and will not be permitted in the break between the end of the contest and a shootout.

* Teams will be permitted to trade or sell international roster spots within the league for the duration of a season. Following the conclusion of the season, all rosters will reset to seven international roster spots per club.

The league has also introduced an injured reserve position to its rosters, allowing clubs to retain a player who has suffered a medically verified season-ending injury without using a roster position. Each club will have one available IR spot for the season.

In game-day rules, teams will submit a 23-player squad at least 48 hours before kickoff of each match, reduced from 27 in 2017. A team’s 18-player game-day roster can contain a maximum of five players signed to USL Academy contracts.