According to reports, Simeone held a conversation with Alvarez and then decided to start him.

The Argentine player started at Anfield, although Simeone had said before the match that he was not yet ready to be in the starting lineup. A conversation between the two changed everything.
About one and a half hours before kickoff, the surprise arrived: Julian Alvarez was named in the starting lineup. Before the match, Simeone's only clear statement had been the opposite, as he said: "He is still in a growth stage, but he is not ready to start yet." However, in the end, Simeone chose the Argentine forward for his first start of the season. This summer, Alvarez experienced a difficult period due to his desire to leave and the complicated process of returning to the Metropolitano. At Tuesday's press conference, Simeone had also referred vaguely to "Julian's issue." But this time, he backed Alvarez, and the result was generally positive. Alvarez's reintegration is progressing, and the team's dressing room is also working on it. The coach understands that the forward is not yet at his best in many areas, but he also knows that the Champions League in particular can bring out Alvarez's motivation. Last season, he scored more goals in European competition (10) than in the league (8), and he scored against every knockout-stage opponent: Club Brugge, Tottenham Hotspur, Barcelona and Arsenal. After the match, Simeone said: "Why did I make the change? I got up in the morning and spoke with him for a while, and I saw that he was in good shape. Fortunately, I chose to put him in because he played the kind of match I expected from him." Before this match, Alvarez had already missed games against Malaga and Sevilla. His debut against Villarreal was also almost unnoticeable, and his appearance in Bilbao was only average, so outside expectations were not especially high. But people saw an Alvarez they had not seen for a long time. He was highly involved, worked hard, and looked more threatening in front of goal. In the fifth minute, he tried a shot that went straight toward Alisson. In the 27th minute, his effort was more dangerous, and the Brazilian goalkeeper made a diving save to stop the shot heading toward the far post. During that period, Alvarez also provided an assist, helping Llorente score in a one-on-one situation to make it 0-1. The second half was more difficult for Alvarez. After a long absence from high-intensity matches, it was difficult for him to last the full 90 minutes at Anfield's pace. Araujo then arrived late in a challenge and kicked his ankle, making things worse. The Atletico forward went down in pain and later waited on the sideline for a minute. However, Alvarez was not substituted. He kept looking for the ball and, together with Jonathan David and Lewandowski, supported the attack in the closing stages. He then used his third shot of the match to try to make it 2-2. "He controlled the ball throughout the match, for the entire 90 minutes, from the first minute to the 90th. That makes me very happy," Simeone analyzed after the game. This was not the best version of Alvarez, but it was already a good performance. Simeone created a surprise by starting a player who had originally been considered unlikely to start and almost achieved the desired result. His assist in the 0-1 situation showed that the forward remains a player with great ability, and he does seem to find his rhythm more easily in the Champions League. Atletico's next European match will return to the Metropolitano, with Manchester United as the opponent on October 13. After that there will also be the city derby and the international break... which will be another matter.