Adelaide United players have been urged to improve their discipline as they attempt to snap a two-game A-League Men winless run.

The Reds return to Coopers Stadium to face Newcastle on Tuesday amid a dip in form and after a couple of frustrating lapses in discipline.

United are without Ben Halloran through suspension after he picked up two yellow cards in their 3-1 loss to Wellington, while Isaias is only just returning from his own ban after doing the same in Adelaide's 1-1 draw with Brisbane.

"We've addressed it," coach Carl Veart said.

"It's something that the playing group set very high standards for themselves.

"But in the heat of the moment, sometimes you can get a little bit (ahead) of yourself.

"But we spoke about it with the coaching staff to the playing group and they will make certain adjustments."

Attacker Zach Clough will return from a long-term injury in an important boost for the Reds.

Clough has played just one game this season after 13 last season.

"We always pencilled in him returning for this week," Veart said.

"We could have pushed him to be ready for the game last week, but it wasn't worth the risk.

"So he's ticked all the boxes to be ready for tomorrow."

The Jets have lost five of their past six games and are coming off a local derby defeat to Central Coast but Veart was wary of Arthur Papas's charges.

"They play a good brand of football and if you allow them to pass the ball around, they can cause you some some issues," Veart said.

"It's important that we keep our defensive block and keep focused and then look to play our brand of football as well.

"They concede more goals than they score, I suppose, so they'd be looking at fixing that up defensively."