Xulu barely played in a two-year horror stay with Chiefs prior to linking up with Maritzburg in August 2017.
The Bafana Bafana international, however, bounced back in style as he was named the PSL Defender of the Season in his first year with the Team of Choice last term.
Buchanan also only played 10 games under then-Amakhosi coach Steve Komphela in two years with the Soweto giants before his contract was terminated in June.
The former Bloemfontein Celtic midfielder subsequently penned a two-year deal with United this month after being assessed by Davids.
"Of course, that is the ultimate; getting someone who hasn't played and getting the Defender of the Season accolade. Of course that should be his target," Davids says of Buchanan.
"It's not me who can do it ... it's up to him. Let's hope he has that motivation to push himself and get his career back on track."
Davids, though, is mindful the 27-year-old may need some time to settle in at United given his lengthy spell on the sidelines.
Buchanan last played competitive football in September 2017 when he came on as a substitute for George Maluleka in a 1-1 draw with Bidvest Wits at FNB Stadium. He was also an unused substitute the following month in a game with Mamelodi Sundowns at Loftus Versfeld Stadium.
"He'll give us something different in midfield. We have a highly talented midfield if you take the team of last season," adds Davids.
"Of course he'll have to adapt to our playing style. Ja, we have to understand that he hasn't played competitive football in a long time regularly. It'll take him time. It'll take him time to adapt, to get to the level of fitness.
"It is very important that we don't give him too much too soon. That increases the risk of getting injured and that is definitely what we don't want to do.
"But once he's fit, once he understands what we are trying to do within our playing style, he'll definitely be on the pitch and give us something that our midfield doesn't have."
Davids and his men head to Potchefstroom today for a pre-season camp. The team is set to meet Golden Arrows in the quarter-finals of the KZN Premier's Cup on July 28 at KwaMashu's Princess Magogo Stadium.