Hurricanes scrum-half TJ Perenara is a doubt for the weekend Super 15 clash with Crusaders after hurting his ankle in a training session on Monday.
If Perenara is ruled out, Chris Eaton will make the step up from the bench with Wellington's Frae Wilson coming in from the Hurricanes' wider training group as back-up.
The Hurricanes lost first-choice halfback Chris Smylie to injury before the season even kicked off.
"I'm not sure how bad it is but he looks a bit sore at the moment," Hammett said.
"We've seen Chris Eaton and how good he's been with the impact he's made when he's come on for the last 20-25 minutes. He offers a different feature to the game."
The coach was also confident Wilson would slot in comfortably, adding: "Frae's been with us right through the campaign in the wider training group. He's very much up to speed with what we're doing and how we're playing the game."
Number eight Victor Vito is expected to be back in the mix this weekend following his calf injury, but fellow loose forward Brad Shields (shoulder) was rated only 50-50 by Hammett.
The injury to Perenara took some of the gloss off the announcement that hooker Dane Coles would be staying for 2013 and 2014, but Hammett was obviously delighted to have kept the dynamic, ball-carrying player at the franchise.
"We're really happy. He's obviously happy here. From my perspective he's made huge gains this year," Hammett said.
"We've always known what his game is like, his ability to run with the ball in the loose but it's probably the tight part of his game and his defensive organisation which has captured my eye. But it hasn't just happened. He's worked really, really hard at that. It's making a big difference."