According to Manu Sainz of AS (via MailOnline's Glen Williams), Bale's value has decreased from €133 million (£119 million) to €80 million (£72 million) because of his consistent fitness woes, and Los Blancos are prepared to cut their losses.
In order to replace the Welshman, Real will go after Mbappe and attempt to scupper Paris Saint-Germain's plan to make the young forward's current loan deal permanent next summer by exploiting the French club's financial fair play problems, the report added.
Mbappe, 18, moved from AS Monaco to PSG on loan in August in the wake of their £200 million signing of Neymar.
Per Ed Aarons in the Guardian, the deal to sign Frenchman Mbappe included a clause for a permanent transfer to be completed next summer worth €180 million (£166 million).
However, it seems Real are keen to attempt to hijack the move and add another Galactico to their squad—that's little surprise, given what a revelation he has been in 2017, per Squawka:
Squawka Football @Squawka
Kylian Mbappé for club & country in 2017: 51 games 🏃 25 goals ⚽️ 12 assists 🅰️ Golden Boy. https://t.co/n0WLK6x9rU2017-10-23 10:16:00
Bale, on the other hand, is a consistent frustration for Real and their fans.
His performances when fit continue to be largely excellent, but he spends too much time on the sidelines.
Per Adam Shergold for MailOnline, the 28-year-old has missed 40 of Real's last 60 matches, and he has just picked up another blow, which is likely to see him out for the rest of the year.
Bale has been hugely successful at Real since he moved to the club from Tottenham Hotspur in 2013 for a then-world-record fee of £85 million.
He has won three UEFA Champions Leagues and a La Liga title, and his Spanish top-flight return for Real stands at 56 goals and 34 assists in 105 appearances, per WhoScored.com.
However, if Real could replace him with teenager Mbappe it may be a sensible long-term move given Bale's injury problems only seem to be increasing with regularity.