According to Jeff Passan, MLB will be using “bubble cities” for the playoffs. American League teams will play in San Diego and in Los Angeles, while National League teams will play in Houston and Arlington. The World Series, per Passan, will be at Globe Life Field in Arlington.
This reduces the amount of travel that teams have to do during the playoffs, reducing the possibility of a COVID-19 exposure as well as minimizing the number of off days needed. In addition, with both Texas parks having retractable roofs, and San Diego and L.A. being, well, San Diego and L.A., it minimizes potential weather issues, as well.