Team SoloMid added a second jungler,
Grig has some NA LCS experience with Echo Fox where he played behind
It is certainly possible that Grig will be playing in the first game but splitting time with MikeYeung as per the original plan.
TSM is notorious for having difficulty finding a jungler that synergizes with the team so it is possible that they believe Grig has something that MikeYeung doesn't. MikeYeung hasn't mentioned any reason why he wouldn't be playing so this will be an interesting story to follow as the NA LCS debuts this weekend.
ICYMI: We've updated @TSM's roster graphic to be in line with their earlier announcement regarding their 2018 #NALCS Summer Split Roster:— lolesports (@lolesports) June 15, 2018
Jungle: @TSM_Grig / @MikeYeunglol
Support: @mithytsm #TSMWIN pic.twitter.com/d55XK4lG7v
Lolesports tweeted a correction that shows that neither MikeYeung or Grig as the starter, but rather, they will split time.
Photo courtesy of Riot Games