The 21-year-old joined the Scottish Championship side in January.
Hearts boss Robbie Neilson has explained that Rangers' style of play made them the perfect club for Billy King to join on loan, but insisted that the 21-year-old's future is still at Tynecastle, The Scottish Sun reports.
The winger joined Mark Warburton's side towards the end of the January transfer window despite making 20 appearances for the Scottish Premiership side in the first half of the season.
And after impressing during his time at Ibrox, The Scottish Sun suggested that Warburton may have wanted to try and tie King down permanently. However, while Neilson admitted that joining the Light Blues was the best move for the youngster's development, he insisted that King will not be leaving his parent club for good.
"Billy definitely has a future here. I think he will be a big player for us next season, with European football and a bigger squad," he told The Scottish Sun.
"Billy will be more established after six months playing regularly at Rangers. I just felt like he needed game time. The way Rangers play suits him down to a tee.
"He can push forward and run at people, play in front of big crowds, get his confidence up."
While King's obvious potential meant that it was always going to be difficult for Warburton to prise him away from Hearts, the fact that the Premiership high-flyers let him leave - albeit temporarily - may have given him confidence that a deal could be agreed.
Although the Scotland under-21 international's role in the Gers side has been predominantly as an energetic substitute brought on to take advantage of tiring opponents, he proved on his debut that he has the ability to make a major impact as he scored a stoppage-time winner against title-rivals Falkirk.
But with promotion almost assured, King's chances of regular game-time may be dealt a blow if Warburton decides to concentrate on the players that he will be able to keep hold of for their first season back in the top flight.