Jonny May has been deputising in the role in recent weeks, but Redpath admits Thomas' ability as a specialist full-back is the main reason for bringing him to the club.
"We're aware that Olly Morgan has a long-term injury and Jonny May is still early in his development," added Redpath.
"The key part was that we knew he could fit into our system. He's played a lot of rugby this year and, playing a position like 15, you need to be playing every week.
"He gives us a genuine option in there and will challenge Olly when he returns to full fitness."
Speaking about his move to the Premiership, Thomas said: "I've played at Kingsholm twice in the last few seasons, once in the Heineken Cup and once in the LV= Cup. Although I was with the opposition, I couldn't help but be impressed by the matchday atmosphere.
"I've also watched a lot of Gloucester matches and they play a great brand of rugby, one that will certainly suit my game and I hope that I can add something to the squad.
"Talking to Bryan and hearing his plans for the future, I'm excited at the prospect of joining the club."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.