diff --git a/osu.Game/Rulesets/Ruleset.cs b/osu.Game/Rulesets/Ruleset.cs
index 89ef6d2d54..cd3ab4f726 100644
--- a/osu.Game/Rulesets/Ruleset.cs
+++ b/osu.Game/Rulesets/Ruleset.cs
@@ -252,7 +252,7 @@ namespace osu.Game.Rulesets
         /// Creates the <see cref="IRulesetConfigManager"/> for this <see cref="Ruleset"/>.
         /// </summary>
         /// <param name="settings">The <see cref="SettingsStore"/> to store the settings.</param>
-        public virtual IRulesetConfigManager CreateConfig(SettingsStore settings) => null;
+        public virtual IRulesetConfigManager? CreateConfig(SettingsStore? settings) => null;
 
         /// <summary>
         /// A unique short name to reference this ruleset in online requests.
diff --git a/osu.Game/Rulesets/RulesetConfigCache.cs b/osu.Game/Rulesets/RulesetConfigCache.cs
index 017214df61..ab44e86048 100644
--- a/osu.Game/Rulesets/RulesetConfigCache.cs
+++ b/osu.Game/Rulesets/RulesetConfigCache.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System;
 using System.Collections.Generic;
 using osu.Framework.Graphics;
@@ -18,7 +16,7 @@ namespace osu.Game.Rulesets
         private readonly RealmAccess realm;
         private readonly RulesetStore rulesets;
 
-        private readonly Dictionary<string, IRulesetConfigManager> configCache = new Dictionary<string, IRulesetConfigManager>();
+        private readonly Dictionary<string, IRulesetConfigManager?> configCache = new Dictionary<string, IRulesetConfigManager?>();
 
         public RulesetConfigCache(RealmAccess realm, RulesetStore rulesets)
         {
@@ -42,7 +40,7 @@ namespace osu.Game.Rulesets
             }
         }
 
-        public IRulesetConfigManager GetConfigFor(Ruleset ruleset)
+        public IRulesetConfigManager? GetConfigFor(Ruleset ruleset)
         {
             if (!IsLoaded)
                 throw new InvalidOperationException($@"Cannot retrieve {nameof(IRulesetConfigManager)} before {nameof(RulesetConfigCache)} has loaded");
diff --git a/osu.Game/Tests/Rulesets/TestRulesetConfigCache.cs b/osu.Game/Tests/Rulesets/TestRulesetConfigCache.cs
index a80154c38e..cf637983d9 100644
--- a/osu.Game/Tests/Rulesets/TestRulesetConfigCache.cs
+++ b/osu.Game/Tests/Rulesets/TestRulesetConfigCache.cs
@@ -1,8 +1,6 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-#nullable disable
-
 using System.Collections.Concurrent;
 using osu.Game.Rulesets;
 using osu.Game.Rulesets.Configuration;
@@ -14,8 +12,8 @@ namespace osu.Game.Tests.Rulesets
     /// </summary>
     public class TestRulesetConfigCache : IRulesetConfigCache
     {
-        private readonly ConcurrentDictionary<string, IRulesetConfigManager> configCache = new ConcurrentDictionary<string, IRulesetConfigManager>();
+        private readonly ConcurrentDictionary<string, IRulesetConfigManager?> configCache = new ConcurrentDictionary<string, IRulesetConfigManager?>();
 
-        public IRulesetConfigManager GetConfigFor(Ruleset ruleset) => configCache.GetOrAdd(ruleset.ShortName, _ => ruleset.CreateConfig(null));
+        public IRulesetConfigManager? GetConfigFor(Ruleset ruleset) => configCache.GetOrAdd(ruleset.ShortName, _ => ruleset.CreateConfig(null));
     }
 }