Holah was in inspirational form for the New Zealand Maori in their victory over the Lions 11 days ago but could not break into the All Blacks squad as head coach Graham Henry opted for McCaw as the only specialist open-side flanker.
McCaw expects to be fit for Saturday's Test in Christchurch - he has taken a part in training this week - but Holah has been called up from the Junior All Blacks tour of Australia as a precautionary measure.
"My experience is that I can play and train with this niggle and it usually comes right after a few days," said McCaw.
"But in case it does something unusual, it's good for the team to be ready."
Should McCaw, the Canterbury flanker, be fit to start at Jade Stadium, his battle with Lions open side Neil Back is set to be one of the first Test's key encounters.
The Lions have opted for Back's experience ahead of Martyn Williams in an attempt to counter and neutralise a player many believe to be the best in the world.
It would be a small bonus for the Lions is McCaw is ruled out, but Holah has been in top form in recent weeks and he gave Williams and the Lions a torrid time in Hamilton.
Holah has been training with the Junior All Blacks and had been on the bench for their game against Queensland.
Henry said: "All the signs are that his (McCaw's) back will be fine, but backs can be a little unpredictable so we've taken this extra step.
"We know Marty is in good form and has stayed sharp in recent weeks. That's part of the value of the Junior All Blacks tour."