The game on Friday (Saturday AEDT) comes after more than 200 people died in the massive floods in the Valencia region, and with the club still trying to overcome poor results and ongoing fan protests against Singaporean owner Peter Lim.
Valencia were in last place at the time, with only two victories and seven points from 11 matches.
Now they're second to last with 12 points from 17 games, having won only once since the postponement.
The club were prompted to replace coach Ruben Baraja with Carlos Corberan during the Christmas break.
"We expect an opponent that may be extra motivated after changing their coach," Madrid manager Carlo Ancelotti said on Thursday.
"We've looked how he coached at West Brom, and we'll see how he will adapt to the players he has at Valencia now."
Madrid finished the year by winning the Club World Cup and beating Sevilla 4-2 in the league.
A draw on Friday would be enough to put Ancelotti's team back in first place, tied on points with Atletico Madrid but ahead on goal difference.
A win would leave Madrid in sole possession of the top spot and give them a five-point gap to third-placed Barcelona.
Corberan arrived from English Championship club West Brom on a contract through June 2027 with the task of revitalising Valencia and taking the club out of the relegation zone, though not even a win on Friday would be enough to move the team out of the bottom three as they trail 18th-placed Espanyol by three points.
The managerial change came after Valencia were held at home by Alaves in their last game of the year, prompting increased protests by fans against Lim, whom they accuse of using Valencia purely as a business venture.
The November 2 match against Madrid had to be postponed as Valencia's Mestalla Stadium became a base to help the victims of the flash floods that caused havoc in the region. The club also had Copa del Rey games postponed because of the floods.
Barcelona and Atletico Madrid will be playing round-of-32 games in the Copa del Rey on Saturday, with Atletico facing third-division club Marbella while Barca — who lost their last two league games of 2024 — take on fourth-division Barbastro.
Other La Liga clubs playing in the Copa del Rey this weekend include Sevilla, Real Betis, Rayo Vallecano, Athletic Bilbao, Celta Vigo and Real Sociedad.
Madrid's Copa del Rey game against fifth-division club Deportiva Minera will be on Monday, while Valencia will play second-tier team Eldense on Tuesday.
