With Dave Lewis currently sidelined with an elbow injury and fellow scrum-half Haydn Thomas having taken a bang to the head in last Friday's win at Gloucester, Chiefs head coach Rob Baxter is keen to ensure he has sufficient cover in the half-back role.
Phibbs - who is in his second spell with the Devon club - initially joined a few weeks ago on trial, but his efforts in both training and for the Braves in the Aviva Premiership A League have clearly impressed Baxter to reward the 32-year-old with a deal.
Sydney-born Phibbs previously joined the Chiefs on a short-term deal three years ago and was kept on for the season, making 11 appearances before signing for Leicester Tigers.
He later signed a two-year deal with London Irish in February 2013, but was released this summer after breaking a foot during pre-season last year.
“We’re going to sign him (Phibbs) on a short-term deal, he’ll be here for a couple of months and then we’ll reassess the situation,” said Baxter. “He’s a good player, he’s someone we like and we’ve seen him before so we’re quite comfortable to get him down here.
“He’s very aware he hasn’t played that much recently so we have to get him up to speed and give him opportunities in training and the A League and see how he goes.
“If he goes well enough he’ll get game time, or if things like this happen and injuries occur he’ll be in contention. It’s good that we got him down when we did and it’s given us a bit of cover for a second injury, which we were hoping wouldn’t happen.
“Pat’s training really well, we’ve not had any fitness issues with him so it looks like a good move to have him down here.”