BLUES defender Paul Bower has admitted spots in the senior line-up are up for grabs following Carlton's 53-point loss to Collingwood at the MCG on Sunday.

With coach Brett Ratten making a stand after the disappointing 20-point loss against Essendon in round three by dumping key defenders Jarrad Waite and Bret Thornton, Bower admitted he and the rest of the squad are on notice.

“You have guys like Bret Thornton, Jarrad Waite and Chris Johnson keep pushing you to keep you on your toes,” Bower told carltonfc.com.au.

“You see good players missing out, which hasn’t been the case over the years.”

Bower was disappointed that Carlton couldn’t build on their momentum after its 36-point win over Geelong the previous week. The Blues were in the hunt with a quarter to play against the Magpies, but were outscored seven goals to three in the final term.

“After coming off a good win last week, we were in it until three-quarter time - they just got hold of us at the end,” he said.

“They used their momentum really well. They had a five-minute patch at the start of the second quarter and the end of the third quarter and just really set off from us - they really hurt us on the scoreboard.”

“I don’t think (the margin) really reflected the performance, but a loss is a loss. We’re pretty gutted - we will have to go through the review and move forward next week against St Kilda.”

Bower was not surprised by the performance of Setanta O’hAilpin - who kicked five goals - with the 22-year old seeing first-hand the progress of the Irishman on the training track.

“I do a fair bit with him - he has trimmed down and is moving a lot better than he has previously,” he said.

“The delivery into the forward line wasn’t great, but he somehow managed to make the most of his opportunities.”

Returning from a leg injury that has had him sidelined since round one, Bower managed to gather 31 possessions while keeping his opponent Travis Cloke to just two goals for the match.