According to Récord, Esteban Solari revealed that Pumas wanted to retain Guillermo Martínez but understands the players' needs. Solari said he was clear with Guillermo Martínez from the first day and told him he was counting on him. In alignment with the club's management, Guillermo Martínez was offered a contract renewal, which he did not accept. Martínez later brought an offer from Tigres, and the decision for his departure was made in conjunction with the club, taking into account the economic offer and the fact that his contract was due to end in three months.

According to Récord, Guillermo Martínez has arrived in Monterrey to join Tigres. Martínez stated that since he learned of Tigres' interest, he knew he wanted to join the club. He also highlighted the stability the move provides for his family and his desire to compete for a position that allows him to stay in contention for a call-up to the Mexican national team. Martínez expressed his excitement and commitment to joining Tigres, and called it a great honor to wear the shirt.

According to César Luis Merlo, Tigres has made the transfer of Guillermo Martínez from Pumas official. The 31-year-old Mexican centre-forward's time at Pumas began in January 2024. The player has joined on a permanent transfer and signed a contract until June 2029. He has 14 caps and 3 goals for Mexico. His current market value is €1.50m, according to Transfermarkt.