Marshall told NRL 360: "I was a little bit shocked and disappointed that I got dropped.
"Any player would be in that position. If you're competitive and you want to be part of the team, of course you are going to be disappointed.
"What the coach has done has really put everyone on notice that we're looking for consistency, so you can't go up one week and down the next."
But the SMH reported there is "also a fear internally at the club that it may backfire on Maguire, who has relied so heavily on Marshall to be the conduit between him and the players."
It wondered if problems would now arise "if the veteran feels disrespected by Maguire's decision".
Marshall's contract ends this year. He has been the man of the match in two wins this year, and is near the top of the Dally M leaderboard.
Most expected the 35-year-old would return to the Tigers in 2021 but that is now in doubt, after Maguire promoted Josh Reynolds to the No. 6 jersey against Canberra this weekend.
It was Maguire who returned Marshall to the Kiwis in 2019, after a seven year absence, appointing him to the captaincy as well. And Marshall is reportedly involved in Wests steam selection and recruitment decisions.
But after losing to the struggling Titans, Maguire said Marshall "didn't meet the standards".
Marshall made an emotional return to the black jersey last year and his career had appeared to be gaining even more momentum this season until the shock selection decision this week.
Wests icon Robbie Farah appeared very surprised, saying Marshall was a great trainer and there were other players who could count themselves lucky not to have been chopped.
"They've cut the head off the leader," said Farrah, who thought Maguire was trying to get a reaction from his team. He hoped Marshall would quickly return.
