The Hammers forward revealed that David Moyes has tried to implement a tactical change this season but it "hasn't worked" as the club are in the Premier League relegation zone.
Speaking on the Footballer's Football Podcast, Antonio said: "We've changed the mark from let's not get relegated to let's push for the Champions League. We were jumping steps.
"We tried to change our philosophy. You can see, this season, we haven't played the same way we've been playing the last two years. We've changed it slightly. We've brought in players to play through the thirds."
The player continued: "You can see over the last few games, we've conceded more goals on counter-attacks than we ever had in the last two years. We're open way more, expansive.
"Teams are countering us the way we would have countered them before. It's a transition. We're trying to transition to become a bigger team and, I've got to be honest, it ain't working."
Despite his blunt verdict on West Ham's tactical switch, Antonio is convinced that the team has the players to pull off the tactical switch.
He said: "At the back we've got Kurt Zouma, Thilo Kehrer who plays for Germany and Aaron Cresswell - they're all good on the ball.
"Declan Rice and Paqueta in midfield, Jarrod Bowen, Scamacca, Benrahma. We've got the players who can do it, but it's just getting it to work.
"We knew our philosophy, our identity over the last two years, so trying to find a new one - you see it happening. Leicester won the league and nearly got relegated the next season. It happens."