Celta Vigo forward Iago Aspas has said that Real Madrid were keen to sign him last summer before choosing to re-sign Mariano.
Aspas has been La Liga's highest-scoring Spaniard for the last two years, and was reportedly a target for Real Madrid earlier this year.
The Spain international has now said that the European champions, who face Celta Vigo on Sunday, did hold an interest in him, though they did not make a formal approach.
"They didn't contact me directly but it's true that there was an interest," Aspas said. "They signed Mariano to fill the void of a No. 9."
Madrid, who sold their all-time top scorer Cristiano Ronaldo to Juventus for €100 million in July, chose to bring Mariano back after the striker spent a season at Lyon, with teenager Vinicius Jr. also joining up with the first team.
Aspas said Madrid "have the best players in the world" but that they have not recovered from the departure of Ronaldo to Juve.
"Cristiano Ronaldo added a lot of goals and covered Real Madrid's weaknesses," he said.
Aspas had disappointing spells earlier in his career at Liverpool and Sevilla before returning in 2015 to Celta, where he has flourished.
The 31-year-old has scored eight goals in 11 league starts for Celta so far this season, and when asked about his future, said he was happy at the club but did not rule out a move away.
"I always said that in football you never know what can happen but I have a four-year contract with Celta and I'm very happy here," Aspas said.