Manchester United made contact to gauge Maatsen's availability, but were told by Aston Villa that the Netherlands international is not for sale. Rather than risk losing him for nothing further down the line, Villa's response has been to move towards handing Maatsen new and improved terms, underlining their intention to keep him at the club.
United's interest in a left-back is not confined to Maatsen.
Fabrizio Romano has indicated the Old Trafford club will sign a player in that position before the window closes, though he stopped short of naming a specific target.
"Just as a comparison, remember when United signed Sergio Reguilon from Tottenham on loan - something similar," Romano said.
"Obviously, I'm not saying it's that exact profile again, but that kind of player. An experienced left-back who can provide competition and who also has an international profile.
"Manchester United are exploring this kind of option. Left-back is expected to be an area United want to improve before the deadline. I expect them to sign there."
The comments suggest United are now more likely to pursue an experienced squad option along the lines of Reguilon's loan spell rather than a marquee signing. With Maatsen effectively ruled out and Villa standing firm, United's search for reinforcements at the position looks set to continue into the closing days of the window.
United's need at left-back stems from a lack of senior cover behind Luke Shaw, whose fitness has been a recurring concern, and the club is understood to have already been rebuffed in earlier attempts to source a solution elsewhere in Europe. For Villa, meanwhile, securing Maatsen's long-term future removes one of the summer's few remaining uncertainties in defence.