South Africa's Justin Harding made the most of his late addition to the tournament with a flawless opening 65, but fellow LIV rebel Ian Poulter slumped to an eight-over-par 78.
Harding's fellow South African Branden Grace - who won the second LIV event in Portland - was also added to the field on Tuesday, but while he returned a 69 and Otaegui a 71.