"The safety of our players is paramount," Umaga said. "We did talk to them about it. We'll see where it goes from there. They're aware of it, I think everyone is now, it's a bit of a hot topic, so I'm sure they'll act on it."
Umaga's greater priority is to attempt to coach his team to a victory against a high-flying Chiefs team leading the competition and earning plaudits all over the world with their ambitious, free-flowing attack. He referred to them as "probably the hottest team in Super Rugby at the moment" .
For that he has stuck with his backline which did the job, just, against the Jaguares. Piers Francis has recovered from a knock to his funny bone to partner Rene Ranger in the midfield, Umaga happy with the way the Englishman took to his first match at this level.
The pair will be called on to attempt to contain the attacking talents of second-five Charlie Ngatai, who scored four tries against the Force, and Umaga will hope the lapses of concentration which affected fullback Visinia and wing Tevita Li against the Jaguares don't strike again at the headquarters of a team who have gone to new levels this season.
"They are probably what everybody wants to be in terms of culture and commitment to each other. I think every team is aware of that and trying to replicate that. We know they will come out motivated. They've got plenty of confidence and are running on a high. For us, we've just got to try to match that and do what we do and enjoy it."
Asked if the key to victory was denying the Chiefs the ball for 80 minutes, Umaga replied: "If we don't run out of puff. That's probably a big thing. They're very good at looking after the ball and they can sustain that throughout the game."
Umaga said regular skipper Kaino was recovering well from his shoulder problem suffered almost a fortnight ago against the Reds.
Blues team to play the Chiefs at Waikato Stadium on Friday:
Lolagi Visinia, Rieko Ioane, Rene Ranger, Piers Francis, Tevita Li, Ihaia West, Bryn Hall, Steven Luatua, Blake Gibson, Joe Edwards, Josh Bekhuis, Hoani Matenga, Charlie Faumuina, James Parsons (c), Sam Prattley.
Reserves: Quentin MacDonald, Namatahi Waa, Ofa Tu'ungafasi, Akira Ioane, Kara Pryor, Billy Guyton, Matt McGahan, George Moala.