A number of Ibrox stars will likely attract interest this summer following a hugely successful season with the club winning the Premiership title at a canter and performing well in Europe.
Borna Barisic, Glen Kamara, Alfredo Morelos and Kent are just some of the Rangers figures expected to feature in rumour mills and gossip columns.
Club chiefs have admitted that part of the club’s financial strategy is to make profit through player investment and sales.
For Ferguson, now manager at Kelty Hearts, winger Kent is the player the club needs to hang on to most.
The £7million signing from Liverpool showed his talent once more against Celtic at the weekend and has had previous interest from Leeds United.
"If there's one player Rangers really need to keep it's Ryan Kent - they've got to,” Ferguson told Go Radio.
"I know there will be clubs down south that want him and they've got so much money. But I'm sure the manager knows if he's going to lose one player, he's got to make sure it's not Ryan Kent."
The 24-year-old has had his most productive season, registering double figures in both goals and assists.
"He's shown over the last few months a real level of consistency to his game,” Ferguson said.
"He is a game changer, a match winner – he's been exceptional.
"We just need to keep a hold of him, it's so important that Rangers try to do that."