Blues to unleash Sonny Bill in Dunedin?

The 31-year-old has been out of action since picking up a bad Achilles injury while playing for New Zealand Sevens at last year's Rio Olympics in August.

"It's looking good," Blues coach Tana Umaga told Veitch on Sport.

"He has been training with us, and it's how he feels after he trains.

"If he can get many days where he feels good after training, then that's the process we're going through at the moment, where he's pain-free after one training, and then he can get through a whole week of training.

"It's good [for him] to be back, but it's hard to say whether it's this weekend, next weekend or after the bye."

Loose forward Steven Luatua could also feature against the Highlanders as he has served his four-week suspension.

Meanwhile, the Auckland-based side will be without flyhalf Ihaia West for the match in Dunedin.

West injured his ankle in the scrappy win over the Western Force in Round Six and could be out for a month.

Sources: Veitch on Sport (newstalkzb.co.nz), NZ Herald & stuff.co.nz