diff --git a/spec/System/TestSkills_spec.lua b/spec/System/TestSkills_spec.lua
index 3afa41ce0..b1d1efbb2 100644
--- a/spec/System/TestSkills_spec.lua
+++ b/spec/System/TestSkills_spec.lua
@@ -245,4 +245,25 @@ describe("TestSkills", function()
 
 		assert.True(build.calcsTab.calcsOutput.Cooldown == 10)
 	end)
-end)
\ No newline at end of file
+
+	it("Test active gem DPS sorting estimates replacement skills", function()
+		build.itemsTab:CreateDisplayItemFromRaw([[
+			New Item
+			Bombard Crossbow
+			Quality: 0
+		]])
+		build.itemsTab:AddDisplayItem()
+		runCallback("OnFrame")
+
+		build.skillsTab:PasteSocketGroup("Oil Grenade 20/0  1")
+		runCallback("OnFrame")
+
+		build.skillsTab.sortGemsByDPS = true
+		build.skillsTab.sortGemsByDPSField = "CombinedDPS"
+		local activeGemSelect = build.skillsTab.gemSlots[1].nameSpec
+		activeGemSelect:UpdateSortCache()
+
+		local _, explosiveGrenade = build.skillsTab:FindSkillGem("Explosive Grenade")
+		assert.True(activeGemSelect.sortCache.dpsCalculated["Default:" .. explosiveGrenade.id])
+	end)
+end)
diff --git a/src/Classes/GemSelectControl.lua b/src/Classes/GemSelectControl.lua
index f3b9e11b6..d4ccca3ee 100644
--- a/src/Classes/GemSelectControl.lua
+++ b/src/Classes/GemSelectControl.lua
@@ -246,6 +246,7 @@ function GemSelectClass:UpdateSortCache()
 		canSupport = { },
 		dps = { },
 		dpsColor = { },
+		dpsCalculated = { },
 		sortType = self.skillsTab.sortGemsByDPSField
 	}
 	self.sortCache = sortCache
@@ -300,14 +301,19 @@ function GemSelectClass:UpdateSortCache()
 	local calcFunc, calcBase = self.skillsTab.build.calcsTab:GetMiscCalculator(self.build)
 	-- Check for nil because some fields may not be populated, default to 0
 	local baseDPS = (dpsField == "FullDPS" and calcBase[dpsField] ~= nil and calcBase[dpsField]) or (calcBase.Minion and calcBase.Minion.CombinedDPS) or (calcBase[dpsField] ~= nil and calcBase[dpsField]) or 0
+	sortCache.baseDPS = baseDPS
 
 	for gemId, gemData in pairs(self.gems) do
 		sortCache.dps[gemId] = baseDPS
-		-- Ignore gems that don't support the active skill
-		if sortCache.canSupport[gemId] or (gemData.grantedEffect.hasGlobalEffect and not gemData.grantedEffect.support) then
+		local canEstimateDPS = sortCache.canSupport[gemId]
+			or (gemData.grantedEffect.hasGlobalEffect and not gemData.grantedEffect.support)
+			or (self.index == 1 and not gemData.grantedEffect.support)
+		-- Ignore gems that cannot affect the active skill or replace the active gem
+		if canEstimateDPS then
 			local output = self:CalcOutputWithThisGem(calcFunc, gemData, useFullDPS, fastCalcOptions, calcBase)
 			-- Check for nil because some fields may not be populated, default to 0
 			sortCache.dps[gemId] = (dpsField == "FullDPS" and output[dpsField] ~= nil and output[dpsField]) or (output.Minion and output.Minion.CombinedDPS) or (output[dpsField] ~= nil and output[dpsField]) or 0
+			sortCache.dpsCalculated[gemId] = true
 		end
 		-- Color based on the DPS
 		if sortCache.dps[gemId] > baseDPS then
@@ -438,6 +444,9 @@ function GemSelectClass:Draw(viewPort, noTooltip)
 				elseif gemData.grantedEffect.hasGlobalEffect then
 					SetDrawColor(self.sortCache.dpsColor[gemId])
 					DrawString(width - 4 - height / 2 - (scrollBar.enabled and 18 or 0), y - 2, "CENTER_X", height, "VAR", "+")
+				elseif self.sortCache.dpsCalculated[gemId] and self.sortCache.dps[gemId] ~= self.sortCache.baseDPS then
+					SetDrawColor(self.sortCache.dpsColor[gemId])
+					DrawString(width - 4 - height / 2 - (scrollBar.enabled and 18 or 0), y - 2, "CENTER_X", height, "VAR", "+")
 				end
 			end
 		end
@@ -907,4 +916,4 @@ function GemSelectClass:OnKeyUp(key)
 	end
 	local newSel = self.EditControl:OnKeyUp(key)
 	return newSel == self.EditControl and self or newSel
-end
\ No newline at end of file
+end