A downhole tool includes a base pipe having an opening formed radially-therethrough. The downhole tool also includes a valve positioned at least partially within the opening. The valve includes a dissolvable insert and an impediment. The dissolvable insert prevents the impediment from contacting a seat of the valve such that the valve permits fluid flow in both axial directions through the valve. After the dissolvable insert dissolves, the impediment contacts the seat such that the valve permits fluid flow in one axial direction through the valve but prevents fluid flow in the opposing axial direction through the valve.