https://goo.gl/sxjJrF
https://www.lolesports.com/en_US/worlds/world_championship_2018/about
3.2 Roster Requirements
Each team is required to maintain, at all times during the WCE, five players in the starting lineup (“Starters”), one substitute player (“Reserve”), and a head coach (collectively, the “Active Roster”). If any of the Active Roster is not present onsite,then the team is subject to penalties. Any penalty may be waived by WCE officials in situations deemed by WCE officials to be an emergency.
所以还是只能带一个正式替补
此外，还有紧急替补规则
3 Seventh Player Requirements
A team is required to maintain a second substitute player (the “SeventhPlayer”) where (i) the team’s Starters are comprised of three Residentplayers and two Non-Resident players; and (ii) the team’s Reserve is a Non-Resident player. In this circumstance the team is required to maintain a Seventh Player that is a Resident player. This Seventh Player requirement is intended to protect against situations where a Resident Version 18.4; September 13, 2018 7 player becomes unable to play at WCE and the
team would be unable to field a roster with its Non-Resident Reserve due to the prohibition of three Non-Resident players as Starters.
如果先发五人中有两个外援，且正式替补又是外援，那队伍按规则必须要带一个非外援的
紧急替补（强制要带），怕你搞到最后变上三个韩国人打
其他应该都一样 紧急替补只有不可抗拒因素才能上场