Wayne Mardle says James Wade's uncharacteristic outburst could see a play-off position slip from his grasp.
The Machine spoke out before his clash with Raymond van Barneveld in Birmingham last week, saying that the Dutchman was "not good enough" to beat him - only to be crushed 7-2 at the oche.
He followed that up with defeats against both Simon Whitlock and Andy Hamilton in Liverpool and now a seemingly guaranteed berth at finals night is in serious doubt.
"Everything was going so well up until last week," Mardle told Sky Sports. "He came out with a tirade against Barney saying 'he doesn't beat me' and he got walloped 7-2.
"Tonight he didn't play bad, let's get that right, but he didn't convert the chances that he had. Losing twice in Liverpool is a darting disaster. He was looking like he had a place wrapped up.
"The Barney thing, the tirade against him, I didn't quite get it. Maybe that was him feeling the pressure, but even though he played well tonight he didn't convert the chances.
"That's un-Wade-like. He usually gets results."
Wade (16 points) plays an in-form Phil Taylor on the final night of the regular season in Newcastle and could easily be overtaken by the two players immediately below him.
Robert Thornton (15 points) plays Michael van Gerwen and Van Barneveld next Thursday, while Simon Whitlock (14 points) plays Van Barneveld and Adrian Lewis in a three-way tussle to claim the final place at the O2 Arena.
And Sky Sports pundit Mardle says all three men would be worthy of a top-four spot.
He said: "Whitlock was looking all but out of it and now he is well in the running. Fourth place is up for grabs and it's good to see.
"If Whitlock can win his first match and beat Barney then the pressure will be on Wade and Thornton. If they don't produce he could go on and nick a place.
"Whitlock just escaped relegation by the skin of his teeth so to qualify for a play-off place would be a monumental effort. It would be brilliant.
"It's been a brilliant Premier League and the addition of relegation has made it from the start. Since Week Nine Judgement Night it's all been about the play-offs and now it's come to that point where three people are playing off for it. It's great the way it works like that. It proves the format is right.
"Whoever qualifies in that fourth spot is a potential champ. Whitlock got beat in the final last year, Wade has won it before and Robert Thornton has played the darts of his life.
"They all deserve it, but unfortunately two are going to miss out."