bottom of the batting order
Baseball term referring to the lower part of the batting lineup, typically batters 7 through 9.
Today the bottom of the order hit well, leading to a lot of runs.
上位打線 refers to the top of the batting order (batters 1–3), while 下位打線 is the bottom (batters 7–9).
クリーンナップ is the heart of the order (batters 3–5), distinct from the bottom of the order.
Compound of 下位 (lower rank) and 打線 (batting lineup).