diff --git a/Mage.Sets/src/mage/sets/timespiral/QuilledSliver.java b/Mage.Sets/src/mage/sets/timespiral/QuilledSliver.java
index e2383f61e9..1f382c85aa 100644
--- a/Mage.Sets/src/mage/sets/timespiral/QuilledSliver.java
+++ b/Mage.Sets/src/mage/sets/timespiral/QuilledSliver.java
@@ -30,11 +30,11 @@ package mage.sets.timespiral;
 import java.util.UUID;
 import mage.MageInt;
 import mage.abilities.Ability;
-import mage.abilities.common.SimpleStaticAbility;
 import mage.abilities.common.SimpleActivatedAbility;
+import mage.abilities.common.SimpleStaticAbility;
 import mage.abilities.costs.common.TapSourceCost;
-import mage.abilities.effects.common.continuous.GainAbilityAllEffect;
 import mage.abilities.effects.common.DamageTargetEffect;
+import mage.abilities.effects.common.continuous.GainAbilityAllEffect;
 import mage.cards.CardImpl;
 import mage.constants.CardType;
 import mage.constants.Duration;
@@ -47,7 +47,8 @@ import mage.target.common.TargetAttackingOrBlockingCreature;
  *
  * @author HanClinto
  *
- * A relatively straightforward merge between GemhideSliver.java and CrossbowInfantry.java
+ * A relatively straightforward merge between GemhideSliver.java and
+ * CrossbowInfantry.java
  */
 public class QuilledSliver extends CardImpl {
 
@@ -78,4 +79,4 @@ public class QuilledSliver extends CardImpl {
     public QuilledSliver copy() {
         return new QuilledSliver(this);
     }
-}
\ No newline at end of file
+}
diff --git a/Mage/src/main/java/mage/cards/CardImpl.java b/Mage/src/main/java/mage/cards/CardImpl.java
index d890e5561d..8beaabca2b 100644
--- a/Mage/src/main/java/mage/cards/CardImpl.java
+++ b/Mage/src/main/java/mage/cards/CardImpl.java
@@ -29,7 +29,6 @@ package mage.cards;
 
 import java.lang.reflect.Constructor;
 import java.util.*;
-
 import mage.MageObject;
 import mage.MageObjectImpl;
 import mage.Mana;
@@ -53,10 +52,8 @@ import mage.game.command.Commander;
 import mage.game.events.GameEvent;
 import mage.game.events.ZoneChangeEvent;
 import mage.game.permanent.Permanent;
-import mage.game.permanent.PermanentCard;
 import mage.game.stack.Spell;
 import mage.game.stack.StackObject;
-import mage.players.Player;
 import mage.util.GameLog;
 import mage.watchers.Watcher;
 import org.apache.log4j.Logger;
@@ -315,11 +312,11 @@ public abstract class CardImpl extends MageObjectImpl implements Card {
     public String getTokenSetCode() {
         return tokenSetCode;
     }
-    
+
     @Override
     public String getTokenDescriptor() {
         return tokenDescriptor;
-    }    
+    }
 
     @Override
     public List<Mana> getMana() {
@@ -342,22 +339,29 @@ public abstract class CardImpl extends MageObjectImpl implements Card {
         Zone fromZone = game.getState().getZone(objectId);
         ZoneChangeEvent event = new ZoneChangeEvent(this.objectId, sourceId, ownerId, fromZone, toZone, appliedEffects);
         ZoneChangeInfo zoneChangeInfo;
-        if (toZone == Zone.LIBRARY) {
-            zoneChangeInfo = new ZoneChangeInfo.Library(event, flag /* put on top */);
-        } else if (toZone == Zone.BATTLEFIELD) {
-            zoneChangeInfo = new ZoneChangeInfo.Battlefield(event, flag /* comes into play tapped */);
-        } else {
-            zoneChangeInfo = new ZoneChangeInfo(event);
+        if (null != toZone) {
+            switch (toZone) {
+                case LIBRARY:
+                    zoneChangeInfo = new ZoneChangeInfo.Library(event, flag /* put on top */);
+                    break;
+                case BATTLEFIELD:
+                    zoneChangeInfo = new ZoneChangeInfo.Battlefield(event, flag /* comes into play tapped */);
+                    break;
+                default:
+                    zoneChangeInfo = new ZoneChangeInfo(event);
+                    break;
+            }
+            return ZonesHandler.moveCard(zoneChangeInfo, game);
         }
-        return ZonesHandler.moveCard(zoneChangeInfo, game);
+        return false;
     }
 
     @Override
     public boolean cast(Game game, Zone fromZone, SpellAbility ability, UUID controllerId) {
         Card mainCard = getMainCard();
         ZoneChangeEvent event = new ZoneChangeEvent(mainCard.getId(), ability.getId(), controllerId, fromZone, Zone.STACK);
-        ZoneChangeInfo.Stack info =
-                new ZoneChangeInfo.Stack(event, new Spell(this, ability.copy(), controllerId, event.getFromZone()));
+        ZoneChangeInfo.Stack info
+                = new ZoneChangeInfo.Stack(event, new Spell(this, ability.copy(), controllerId, event.getFromZone()));
         return ZonesHandler.cast(info, game);
     }
 
@@ -598,7 +602,7 @@ public abstract class CardImpl extends MageObjectImpl implements Card {
                     returnCode = false;
                 }
             }
-            if(finalAmount > 0) {
+            if (finalAmount > 0) {
                 game.fireEvent(GameEvent.getEvent(GameEvent.EventType.COUNTERS_ADDED, objectId, getControllerOrOwner(), counter.getName(), amount));
             }
         } else {
@@ -656,7 +660,7 @@ public abstract class CardImpl extends MageObjectImpl implements Card {
         }
         return super.getColor(game);
     }
-    
+
     @Override
     public List<String> getSubtype(Game game) {
         if (game != null) {
diff --git a/Mage/src/main/java/mage/players/PlayerImpl.java b/Mage/src/main/java/mage/players/PlayerImpl.java
index fe4f3b692c..6a045a8e48 100644
--- a/Mage/src/main/java/mage/players/PlayerImpl.java
+++ b/Mage/src/main/java/mage/players/PlayerImpl.java
@@ -863,8 +863,9 @@ public abstract class PlayerImpl implements Player, Serializable {
     }
 
     @Override
-    public boolean putCardsOnBottomOfLibrary(Cards cards, Game game, Ability source, boolean anyOrder) {
-        if (!cards.isEmpty()) {
+    public boolean putCardsOnBottomOfLibrary(Cards cardsToLibrary, Game game, Ability source, boolean anyOrder) {
+        if (!cardsToLibrary.isEmpty()) {
+            Cards cards = new CardsImpl(cardsToLibrary); // prevent possible ConcurrentModificationException
             if (!anyOrder) {
                 for (UUID objectId : cards) {
                     moveObjectToLibrary(objectId, source == null ? null : source.getSourceId(), game, false, false);