Mederos was born in Santa Clara, Cuba.[1] In 2008, his family obtained travel visas allowing them to travel to Costa Rica, and then they traveled to Mexico and then to the United States. The family were allowed entry into the United States through the wet feet, dry feet policy. They settled in Miami.[2]
The Los Angeles Angels selected Mederos in the sixth round, with the 178th overall selection, of the 2022 Major League Baseball draft.[4] He made his professional debut with the High–A Tri-City Dust Devils, making 6 starts and recording a 5.63 ERA with 15 strikeouts in 16 innings of work.[5] Mederos began the 2023 season with the Double–A Rocket City Trash Pandas, starting 12 contests and registering a 5.98 ERA with 71 strikeouts across 55+2⁄3 innings pitched.[6]
On June 30, 2023, the Angels promoted Mederos to the major leagues for the first time.[7][8][9] In 3 games for Los Angeles, he posted a 9.00 ERA with 3 strikeouts in as many innings. Mederos was optioned to the Triple–A Salt Lake Bees to begin the 2024 season.[10]