COLLINGWOOD coach Mick Malthouse has put the heat on his team before the clash with St Kilda, saying several players, including key playmaker Dale Thomas, had failed to meet expectations this season.

Malthouse said the club's past month had been poor and it needed to quickly turn things around.

"I don't know if it's a season-defining game at round eight but it's going to tell us a little bit about a few players," Malthouse said of the Saints' clash. "To be 3-4 (win-loss record), we haven't played well and we may be on the last line with a few blokes that are just going. Sometimes you can stand still and clubs will go past you."

Malthouse said he was unsure why some players were in a form trough this year, after the Magpies surprised the competition by making it to within a kick of a grand final last year with a mostly young squad.

"I've got a feeling there are a couple of blokes, three or four blokes, that have been very handy players for us that really haven't improved this year for one reason or another," he said. "They are just as mystified as I am; they really can't put their finger on why; they're still doing all the work. That means that either players have gone past those blokes or they just haven't been able to pick up from where they were last year."

Asked specifically about star youngster Thomas, Malthouse conceded the zippy midfielder-forward was among the group he was referring to.

"Dale hasn't played as well as he would like," he said. "Again, it's not through effort, it's just one of those things. I'm sure he'll get out of it, he knows he's got to change his fortunes."

While not named by Malthouse, reigning best and fairest Travis Cloke and midfielder Dane Swan are others who have probably not lived up to the high standards of last season.

Youngsters Harry O'Brien, Tyson Goldsack and Martin Clarke could also be among that group, with O'Brien and Goldsack finding life harder in defence in the absence of experienced pair James Clement and Simon Prestigiacomo.

AAP