The Highlanders are already without loose forwards Dan Pryor (knee) and Shane Christie (mystery illness), but may welcome back No8 Luke Whitelock from a shoulder injury for the match against the Blues on Saturday night.
Tasman flanker Christie, a Highlanders co-captain last year, has been suffering from an undiagnosed illness which has ruled him out of pre-season and his team's first two matches, and McLeod said it was a frustrating time for the player.
"It's a really slow process and what we do know is that if he increases his intensity in training he feels it physically and with his head."
A boost is a potential return from concussion of fullback Ben Smith. McLeod said the All Blacks No15 was a possibility to return if he passed the team's concussion protocols this week.
The Highlanders will arrive in Auckland after two defeats and will take on a Blues team who impressed early against the Rebels but slipped in their defeat to the Chiefs in Hamilton.
"They have a lot of X-factor across the park and they're putting that all together and they can be a really powerful team," McLeod said. "The challenge for us is not letting them get into their game."