diff --git a/main/src/com/google/refine/sorting/BooleanCriterion.java b/main/src/com/google/refine/sorting/BooleanCriterion.java
index fb101c9d8..1f56c98de 100644
--- a/main/src/com/google/refine/sorting/BooleanCriterion.java
+++ b/main/src/com/google/refine/sorting/BooleanCriterion.java
@@ -53,7 +53,7 @@ public class BooleanCriterion extends Criterion {
                         return s_error;
                     }
                 }
-                return value;
+                return null;
             }
 
             @Override
diff --git a/main/src/com/google/refine/sorting/NumberCriterion.java b/main/src/com/google/refine/sorting/NumberCriterion.java
index b9af38b15..287618c35 100644
--- a/main/src/com/google/refine/sorting/NumberCriterion.java
+++ b/main/src/com/google/refine/sorting/NumberCriterion.java
@@ -66,7 +66,7 @@ public class NumberCriterion extends Criterion {
                     }
                     return s_error;
                 }
-                return value;
+                return null;
             }
 
             @Override
diff --git a/main/tests/server/src/com/google/refine/tests/operations/row/RowReorderOperationTests.java b/main/tests/server/src/com/google/refine/tests/operations/row/RowReorderOperationTests.java
new file mode 100644
index 000000000..c8cbc882e
--- /dev/null
+++ b/main/tests/server/src/com/google/refine/tests/operations/row/RowReorderOperationTests.java
@@ -0,0 +1,53 @@
+package com.google.refine.tests.operations.row;
+
+import java.util.Properties;
+
+import org.json.JSONObject;
+import org.testng.Assert;
+import org.testng.annotations.AfterMethod;
+import org.testng.annotations.BeforeMethod;
+import org.testng.annotations.Test;
+
+import com.google.refine.ProjectManager;
+import com.google.refine.browsing.Engine.Mode;
+import com.google.refine.model.AbstractOperation;
+import com.google.refine.model.Cell;
+import com.google.refine.model.Project;
+import com.google.refine.operations.row.RowReorderOperation;
+import com.google.refine.process.Process;
+import com.google.refine.tests.RefineTest;
+
+public class RowReorderOperationTests extends RefineTest {
+    
+    Project project = null;
+    
+    @BeforeMethod
+    public void setUp() {
+        project = createCSVProject(
+                "key,first\n"+
+                "8,b\n"+
+                ",d\n"+
+                "2,f\n"+
+                "1,h\n");
+    }
+    
+    @AfterMethod
+    public void tearDown() {
+        ProjectManager.singleton.deleteProject(project.id);
+    }
+    
+    @Test
+    public void testSortEmptyString() throws Exception {
+        project.rows.get(1).cells.set(0, new Cell("", null));
+        AbstractOperation op = new RowReorderOperation(
+                Mode.RowBased,
+                new JSONObject("{\"criteria\":[{\"column\":\"key\",\"valueType\":\"number\",\"reverse\":false,\"blankPosition\":2,\"errorPosition\":1}]}"));
+        Process process = op.createProcess(project, new Properties());
+        process.performImmediate();
+        
+        Assert.assertEquals("h", project.rows.get(0).cells.get(1).value);
+        Assert.assertEquals("f", project.rows.get(1).cells.get(1).value);
+        Assert.assertEquals("b", project.rows.get(2).cells.get(1).value);
+        Assert.assertEquals("d", project.rows.get(3).cells.get(1).value);
+    }
+}
\ No newline at end of file