Smith left the Westpac Stadium field after colliding with Rene Ranger in the 70th minute of the dispiriting 34-20 defeat.
The Pitch Side Concussion Assessment has been introduced to Super 15 this season.
Hammett added: "He felt fine straight after the game when I was talking to him, but that doesn't always determine how bad a concussion is."
One of Smith's worst concussions was in 2010 when he blacked out after taking the ball into a tackle.
His most serious eye injury was a detached retina while playing for the Hurricanes last season.
He passed a psychometric concussion test yesterday, with a physical test the next step. If he passes that he can take part in contact training.
Smith's leadership could be crucial against the Reds, who have had a mixed start to the season. They lost the opener against the Brumbies in Canberra but beat biggest rivals the Waratahs at their Suncorp Stadium home at the weekend. The Reds under Ewen McKenzie are often difficult customers at home and adding to the difficulties for the Hurricanes is the late kickoff - 8.20pm local time or 11.20pm in New Zealand.
Also monitoring Smith's recovery will be All Black coach Steve Hansen.
The 30-year-old Smith is said to be taking a sabbatical this year and won't be available for the All Blacks' European tour. With Richard Kahui recovering from shoulder surgery and leaving for Japan at the end of the Super 15, and Tamati Ellison also making a comeback from an operation, Hansen needs options for the No13 jersey.
Tim Nanai-Williams was outstanding there for the Chiefs in the victory over the Highlanders, scoring two tries, but is inexperienced.
Highlander Ben Smith is looming as a safe option, with Rene Ranger also in the frame if he can impress at the Blues this season.
Crusader Robbie Fruean will want to press his claims against Ranger at Eden Park on Friday. It will be the Crusaders' first competition match of the season after a bye in round one.
Highlanders No8 Nasi Manu will spend at least the next three months on the sideline. He dislocated a ligament in his foot during Friday night's match against the Chiefs in Dunedin and will need surgery. APNZ