Maritzburg recruited the left-back this month from Bidvest Wits as part of a swap deal involving Denis Weidlich, while they have also promoted midfielders Ujaun McDonald and Lindokuhle Sithole from their development ranks.
Thlone has penned a three-year with the team, but will miss most of the season with ligament damage.
“Getting in a left-footer in Thlone gives us a bit more balance in our thinking and flexibility,” Davids told the club's website.
“Bokang is an attacking fullback who likes to move forward, making overlapping runs. He’ll give us something we haven’t had over the last few seasons.”
United have struggled to fill the void left by left-back Ruben Cloete's departure in July 2014.
Meanwhile, Team of Choice chairman Farook Kadodia is deliberating over whether to bring in any more players this month.
“I made it clear, and obviously this is something we discussed with the coach, that we don’t need to go out aggressively in this transfer window. One reason is that there is no break for AFCON, so there is not really time for players to come here get match fit.
“We felt that it was not the right time to go to the market and we will focus more on the players we have.
“There are one or two positions which we need to bolster, so we might fly under the radar with a few signings. I don’t think we’re in a crisis stage, but there are one or two players that we need and if they’re available and it suits us then we’ll look at it.”
In other transfer activity, the attack-minded Devon Saal has been loaned to NFD outfit Stellenbosch FC.
Maritzburg, 3-0 victors over Free State Stars last time out, are fifth on the Premiership table with 27 points from 18 matches, and next host Chippa United at Harry Gwala Stadium on Friday (20h00).