diff --git a/Mage.Sets/src/mage/sets/journeyintonyx/BattlefieldThaumaturge.java b/Mage.Sets/src/mage/sets/journeyintonyx/BattlefieldThaumaturge.java
index 1a007690b9..2fed4c52a7 100644
--- a/Mage.Sets/src/mage/sets/journeyintonyx/BattlefieldThaumaturge.java
+++ b/Mage.Sets/src/mage/sets/journeyintonyx/BattlefieldThaumaturge.java
@@ -123,7 +123,7 @@ class BattlefieldThaumaturgeSpellsCostReductionEffect extends CostModificationEf
         if ((abilityToModify instanceof SpellAbility)
                 && abilityToModify.getControllerId().equals(source.getControllerId())) {
             Spell spell = (Spell) game.getStack().getStackObject(abilityToModify.getId());
-            return spell != null && this.filter.match(spell, game);
+            return spell != null && BattlefieldThaumaturgeSpellsCostReductionEffect.filter.match(spell, game);
         }
         return false;
     }
diff --git a/Mage/src/mage/game/GameCommanderImpl.java b/Mage/src/mage/game/GameCommanderImpl.java
index 648c8bea9a..3fc18e5704 100644
--- a/Mage/src/mage/game/GameCommanderImpl.java
+++ b/Mage/src/mage/game/GameCommanderImpl.java
@@ -204,7 +204,7 @@ public abstract class GameCommanderImpl extends GameImpl {
 
     @Override
     public Set<UUID> getOpponents(UUID playerId) {
-        Set<UUID> opponents = new HashSet<UUID>();
+        Set<UUID> opponents = new HashSet<>();
         for (UUID opponentId: this.getPlayer(playerId).getInRange()) {
             if (!opponentId.equals(playerId)) {
                 opponents.add(opponentId);
diff --git a/Mage/src/mage/game/GameImpl.java b/Mage/src/mage/game/GameImpl.java
index f0e9d26c87..45341f6cf0 100644
--- a/Mage/src/mage/game/GameImpl.java
+++ b/Mage/src/mage/game/GameImpl.java
@@ -937,11 +937,16 @@ public abstract class GameImpl implements Game, Serializable {
 
     @Override
     public synchronized void quit(UUID playerId) {
-        Player player = state.getPlayer(playerId);
-        if (player != null) {            
-            player.quit(this);            
-        }else {
-            logger.error(new StringBuilder("quit - player not found - playerId: ").append(playerId));
+        if (state != null) {
+            Player player = state.getPlayer(playerId);
+            if (player != null) {
+                logger.debug(player.getName() + " quits the game");
+                player.quit(this);
+            }else {
+                logger.error(new StringBuilder("quit - player not found - playerId: ").append(playerId));
+            }
+        } else {
+            logger.error(new StringBuilder("quit - state not found - playerId: ").append(playerId));
         }
     }
 
@@ -1841,7 +1846,7 @@ public abstract class GameImpl implements Game, Serializable {
     @Override
     public void leave(UUID playerId) {
         Player player = getPlayer(playerId);
-        if (player.hasLeft()) {
+        if (player == null || player.hasLeft()) {
             return;
         }
         player.leave();