At least two of them and likely all 3 are going to be in the candidates, so this is just going to be an entirely different level of competition. The betting odds put Hikaru at <10% chance to win, which seems about right to me. Hikaru was also in trouble at various times in the FIDE Grand Prix but escaped some very bad positions with draws, which against higher level competition he might not be so lucky.
I'm not necessarily a Hikaru fan, but I enjoyed his post-game recaps after the grand prix matches, because that type of analysis isn't something any other top level players are going to do for fear of revealing some weaknesses that opponents can seize upon (and believe me... Hikaru's opponent's teams will be scouting those videos). However, not caring can only get you so far as the level of competition increases.