According to Fabrizio Romano, Dumfries is the new Real Madrid signing and there are both positives and negatives to it. Dumfries arrives as a direct replacement for Carvajal, who left Real Madrid after competing for a place with Trent. At certain stages, Carvajal ended up losing that battle, although neither of them had a particularly great season.
Trent’s problem was, and still is, his defending, as he does not bring much defensive solidity. Does Dumfries provide that? I do not think he is a top-of-the-top defender, but he is slightly better than Trent in that aspect. Offensively, however, Trent offers much more: long passes, incredible vision and quick decision-making. Dumfries tries to contribute in his own way, with good crosses, but he is more limited on that side of the game.
The battle for the starting spot is between the two, and I still think Trent has a slight advantage, but it is an honest competition: either of them can be the starter.
The key point here is that Dumfries played in an Inter side with three centre-backs, which allowed him to be much more attacking, constantly pushing forward and not having as many direct defensive responsibilities. In a back four, as a more traditional right-back, I am not sure he is quite as reliable, unless Mourinho decides to set Real Madrid up with three centre-backs.
As I said, Dumfries is not a bad player and he brings different qualities compared to Trent. They are almost opposite types of full-backs, but I am not 100% convinced because, regardless of who starts, there is not complete confidence in the defensive side of things.
Conclusion
Dumfries and Trent will compete for the starting right-back spot at Real Madrid now that Carvajal has left. Offensively, I trust Trent more and, defensively, I trust Dumfries slightly more. Even so, Dumfries is not used to playing in a back four with only two centre-backs, since Inter did not use that system.