The Chiefs and the Crusaders have also been hit hard by injury, with the former losing all six of their props from the start of the season, but both have the depth and ability to struggle on regardless. For the inconsistent Blues the misfortune is more damaging.
Halfback and skipper Augustine Pulu has missed the last five matches due to an ankle injury, while All Blacks midfielder Sonny Bill Williams has been out with a wrist injury since the Blues' defeat by the Stormers in Cape Town last month.
Veteran loose forward Jerome Kaino, who tore his hamstring against the Chiefs at Waikato Stadium, could be out for another six weeks.
Midfielder George Moala is out for the season with a chest injury, while lock Scott Scrafton, an excellent performer last year, is also out for the season with a leg problem.
The Blues are 14th of 15 Super Rugby teams, with only two victories this season, and the odds are against them breaking their horror run against New Zealand teams when they face the Highlanders.
The injuries do not only seriously disadvantage the Blues at the weekend, but also during trainings. There are plenty for the serial under-achievers to work on, including being far more aggressive around the contact area, but Umaga will be wary about pushing them too hard there for fear of losing someone else.
It means too that there are fewer experienced players around 21-year-old No10 Stephen Perofeta, a young man with immense promise but one yet to find his feet in terms of game management.
"It seems all the New Zealand Super teams are suffering from a high attrition rate and we are no different," said Umaga, who will name his team on Wednesday. "It is testing the depth of the playing resources around the country as we have seen this week with the likes of Sam Prattley called into the Chiefs.
"It is testing our depth and our resources but at the same time it is giving opportunities to others.
"It is challenging to build momentum when we are changing so many players and now bringing in new faces but we are fortunate that our development team coaches have done such a great job with the next layer of players."
Umaga, in the last year of his three-year deal but likely to be retained by the Blues, can only hope his team's luck changes in a hurry. Another defeat to the Highlanders will be damaging but more injuries on top of it would be almost cruel.
Blues injury list: Otere Black (knee - season), Blake Gibson (shoulder), Glenn Preston (groin, season), Sonny Bill Williams (wrist), Augustine Pulu (foot), Alex Hodgman (wrist), Scott Scrafton (leg - season), Daniel Kirkpatrick (ribs), Melani Nanai (ankle), Jordan Trainor (hand), Matt Johnson (surgery - season), Jerome Kaino (hamstring), George Moala (chest – season), Josh Goodhue (shoulder), Tamati Tua (hand), Gerard Cowley-Tuioti (knee), Caleb Clarke (appendicitis), Michael Collins (hand).
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