Coles, still suffering symptoms from an apparently innocuous incident against the Highlanders in the middle of March, continues his recovery, the toughest part of which probably is the fact that neither he nor anyone else will know when he will available to play again.
It is difficult to know whether concussion is becoming more prevalent this season or if players and medical staff and taking a more cautious approach to symptoms.
There have been a spate of players affected. Crusaders Ryan Crotty and Matt Todd, Chiefs Stephen Donald and Sam McNicol and Blues player Sonny Bill Williams have been recent casualties, with Chiefs midfielder Charlie Ngatai again having symptoms just one match after his year-long absence with the problem.
Hurricanes coach Boyd said after his team's win over the Bulls that Barrett woke with a headache and the decision to withdraw him was made despite him passing all tests.
"Every time he exercised, every time he trained, he got absolutely no symptoms at all," Boyd said.
"But the next morning he woke up with a headache, which probably 80 per cent of the squad did because we're trying to get used to the altitude and trying to get used to the temperature and trying to get used to all sorts of things.
"But when you speak to the medical team, it's like 'what is inducing that?
"Is it a continuation of some head-knock symptoms or what's going on?'
"So we weren't able to differentiate from that and we pulled him out at captain's run."
If wing Nehe Milner-Skudder passes a fitness test on his injured foot today, he will be available to play the Force in Perth.
