The Arsenal defender saw red for hauling down Evanilson in the first-half of their 2-0 defeat at Bournemouth.
Halsey wrote in his column for The Sun: "I had major doubts over William Saliba’s red card and would have stayed with referee Rob Jones’ on-field decision of a caution.
"The Arsenal defender fouled Bournemouth striker Evanilson but was it a clear and obvious error for VAR to intervene?
"It’s a subjective decision, so I didn’t think VAR Jarred Gillett needed to get involved. For the denial of a goalscoring opportunity, we look at four key criteria.
"And I had doubts over three of those.
"The distance between the offence and the goal was lengthy, the general direction of play saw the ball coming across Evanilson and not in front of him and also the location and number of defenders was questionable."
The likelihood of him keeping or gaining control of the ball would have probably been in the favour of the Cherries forward because David Raya was back-pedalling towards his own goal.