After an injury-disrupted first season in the Spanish capital, new Los Blancos boss Jose Mourinho has nudged the the 28-year-old down to third choice at right-back, behind Denzel Dumfries and club captain Fede Valverde.
Trent is unhappy with his current status with the LaLiga giants and could consider a move back to the Premier League - but a return to Liverpool is not on the agenda.
The latest from Football Insider claims Chelsea are prepared to offer him an exit route from Madrid if he becomes available in 2027.
Neither party are looking at a move in the January market, but Xabi Alonso is keen to work with Trent again, after their six months together in Madrid.
Chelsea could test the water with a loan bid in January, which Mourinho may listen to, but a permanent deal will be held back until next summer.