Penrith centre Waqa Blake has been dropped for Friday night's clash against the Wests Tigers for turning up to training late this week.
Blake was omitted from the 21-man squad on Thursday with the club indicating the Fijian international misread the training schedule.
"It's nothing major but disappointing as well," Panthers coach Ivan Cleary said.
"Standards are the most important thing so that's what we've done. It's certainly not what you want but team standards, you hold them really highly.
"We're a team that across the balance of the season haven't been happy with how we've been playing, there's been a lot of injuries and individuals could play better as well.
"The team is the most important thing."
Panthers lock Hame Sele has also withdrawn, from the rematch against coach Ivan Cleary's former club, with a back complaint.
Tyrell Fuimaono will replace Blake in the centres with utility Sione Katoa moving to lock. Jarome Luai and Kaide Ellis are the new players on the bench.
Powerhouse forward Viliame Kikau's chances of playing have improved with the Fijian remaining in the side's 19.
Cleary confirmed Kikau was likely to be late inclusion if he pulls up well on Friday after being cleared of any serious ankle damage earlier in the week.
"He's pretty good, as far as everything went today it's good," Cleary said.
"It's just one of those things where when you've got a pre-existing injury there's a lot of scar tissue and it can be really painful.
"It's a big boost, not just for the team but Billy personal. He's already had a big injury at the beginning of the year and was bummed after the game.
"He's a big part of our team and everyone loves playing with him."
The Panthers are desperate for a victory against the Wests Tigers in Magic Round after four straight losses.
"I think we're all looking forward to the experience and playing well," Cleary said.
"It's just not happening for us regularly enough. We haven't had a lot of rhythm to our game either through just the way the game has gone, or we've made errors at the wrong time.
"If you get rhythm that's when we're at our best. That's what we're looking for."