MLB free agency is officially underway, but the Pirates may not find everything they need on the open market. Pittsburgh has decisions to make on Brandon Lowe and Gregory Soto while also determining how Mitch Keller fits into the offseason plan. The biggest challenge could come if Lowe leaves. His 35 home runs cannot simply be replaced by one player, and the Pirates may ultimately need to turn to the trade market to keep the offense from regressing.