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.
所以還是只能帶一個正式替補
此外，還有緊急替補規則
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.
如果先發五人中有兩個外援，且正式替補又是外援，那隊伍按規則必須要帶一個非外援的
緊急替補（強制要帶），怕你搞到最後變上三個韓國人打
其他應該都一樣 緊急替補只有不可抗拒因素才能上場