Forward Teerasil Daengda, central defender Kiatprawut Saiwaeo and right back Suree Sukha all had recent trials at City and were accompanied to England by Pholchivin.
City were prepared to sign Sukha, but work permit problems thwarted the move.
Pholchivin told The Nation: "All three performed well, not just Suree. However, they considered Suree had a better chance to get into the senior team on the ground of his form and the fact that he was selected as a member of the Asian Cup best eleven in the group stage in July."
Chanvit dismissed the suggestion that Thai players received special treatment during their stay in Manchester and the contract was offered mainly because of the fact that the club owner was a Thai.
"Many see the trial as a privilege but I would say it's an opportunity that the former premier gave to Thai football. Although he could arrange this for us, it was (Sven Goran) Eriksson who has the final say on the issue," he added.