The Blues appear to be at a loss as to why Sonny Bill Williams decided to tape up the Bank of New Zealand advertising on his Super Rugby jersey.
The taped-up collar was obvious when the All Black centre came off the bench in the Blues game against the Highlanders in Dunedin on Saturday night.
It was understood Williams, who is Muslim, covered the logo for religious reasons.
Muslims believe the charging of interest is prohibited by the Quran.
As a part of their collective agreement any player can lodge a conscientious objection to promoting finance, alcohol, tobacco, gambling companies and banks.
Williams was playing his first match in the 15-a-side game since the 2015 World Cup final after recovering from a ruptured Achilles tendon suffered at the Rio Olympics.
RNZ Sport understands Williams had told the Blues he did not want to have BNZ on his jersey, but that they had not made a personalised one for him in time for his return to the playing field on Saturday.
It is also understood that New Zealand Rugby knew of Williams' situation.
A Blues spokesperson said they do not know why the jersey was altered and would be discussing it with Williams and his agent this week.