ANDREW Walker's troublesome knee problems will see him on the sidelines for a few weeks.

The veteran Blue has had his past two years curtailed by a left knee issue that ended his 2014 campaign in July and forced him to have three operations on the joint in the proceeding seven months.

The problem also plagued him last season, when he managed only 12 matches. The 30-year-old is contracted until the end of 2017. 

Carlton coach Brendon Bolton said before training on Friday that the injury was related to Walker’s previous issues.

"It's been a little bit sore. Also tightened up through the rest of his body," Bolton said. 

"It will probably be a few weeks out (for Walker)."

The leadership group member missed five matches earlier this season as he dealt with a troublesome calf. 

Dale Thomas has suffered a similar setback, with a calf concern forcing him out of the team to face West Coast on Sunday at Etihad Stadium. 

"(It will) be a couple of weeks (for Thomas). We'll just wait and see," Bolton said. 

The coach was again unable to give an exact time-frame on captain Marc Murphy's return.

"He's making slow progress every week. Hopefully (he will return) within two or three weeks," Bolton said.

"We're pretty close, but it's hard to lock that down." 

Bolton warned that the Eagles would be a sizeable challenge for his young team. 

"They can score really quickly from stoppages, so we need to be on," he said.

Carlton ranks second-last in clearance differential. 

The Blues are relishing the chance to face one of the stronger teams in the competition. West Coast sit fifth after three consecutive victories and a win would almost certainly propel it into the top-four. 

"We look at teams that have been in the eight and played in finals as a real opportunity to grow, because it's a great chance to benchmark," he said. 

Carlton was on the end of a 60-point loss to third-placed Adelaide last Sunday but Bolton said there had been positive signs from that contest. 

"Even on the weekend, we won multiple turnovers in our forward half, which shows progress," he said. 

"It shows that when our effort and intensity is up, we'll get enough entries.

"When you can see the little steps going forward in games, the spirit's always high. Our challenge though, is to do that for longer."