This will be a longer post - The genesis of this decision goes back to 2017 along with Mitchelton Scott positioning themselves for the future - It's well known that the 'Leaders of the team' were unhappy with the the GC's they were assigned to ride - It's well known that Chaves didn't want to the ride the TDF in 2017, while Yates x 1 wanted to ride the TDF, while Ewan wanted to ride the TDF, though to be fair Ewan wasn't ready for the TDF in 2017 - At the end of October 2017, MS already decided what GT's their leaders would ride in 2017 - In fact the Giro 2018 team was selected in October 2017, long before official routes for GT's were announced, while the TDF squad had 12 riders The team would have two strong GC teams for the Giro and the Vuelta, while the TDF would be sprint focused - It's important to stress all the leaders chose their GC's for 2018.
We have to remember that MS is an Australian team who WANT to have an Aussie as a marquee rider - I will add that IMO, MS made a mistake when they allowed Matthews to go because he could have been the Aussie MARQUEE rider The team knew it would be challenging to keep Yates x 2 and Ewan, and their preference was to keep Ewan and Yates x 1 - MS were fully aware the Australian cycling mafia were STRONGLY encouraging him to change teams, especially as MS is now more of a GC team - MS were fairly confident that EWan would stay, so riding the TDF was a carrot ( and he is ready for the race ) along with the TDF being a shopfront for new sponsors - MS has a somewhat strained relationship with Ewan's mgr ( who manages four from the team ) and they were offended when there was total silence after MS made their contract offer to Ewan - No we'll consider the contract or can you offer us better terms or we refuse the offer - This caused a rethink from MS who are now desperate to keep Yates x 2, as the team can't afford to lose 2 of their leaders - Now dropping Ewan from the team allows MS to offer a bit more support to A.Yates for this TDF and gives Yates x 2 more incentive to stay at MS.
Will add there was some behind the scenes jostling regarding the composition of the team - My understanding is Ewan wanted Kluge in the team who would be part of his sprint train and be invaluable in the TTT which caused feathers to be ruffled - Apparently A.Yates was unphased about these rumblings as he knew he had limited mountain support - I actually feel sorry for Mezgec whose based his own season around the TDF - Anyway MS will need to look for another sprinter because they have a contracted sprint team, except for Kluge for 2019 - So expect MS to try hard for an Ackermann type - Finally Ewan's failure to ride the TDF has nothing to do with him leaving the team - During their history MS always select riders even if they are leaving the team.