diff --git a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
index b7c8f775b857..b7368b6a00fe 100644
--- a/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
+++ b/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/Optimizer.scala
@@ -185,9 +185,9 @@ abstract class Optimizer(catalogManager: CatalogManager)
       RemoveLiteralFromGroupExpressions,
       RemoveRepetitionFromGroupExpressions) :: Nil ++
     operatorOptimizationBatch) :+
-    // This batch rewrites data source plans and should be run after the operator
-    // optimization batch and before any batches that depend on stats.
-    Batch("Data Source Rewrite Rules", Once, dataSourceRewriteRules: _*) :+
+    // This batch rewrites plans after the operator optimization and
+    // before any batches that depend on stats.
+    Batch("Pre CBO Rules", Once, preCBORules: _*) :+
     // This batch pushes filters and projections into scan nodes. Before this batch, the logical
     // plan may contain nodes that do not report stats. Anything that uses stats must run after
     // this batch.
@@ -293,10 +293,10 @@ abstract class Optimizer(catalogManager: CatalogManager)
   def earlyScanPushDownRules: Seq[Rule[LogicalPlan]] = Nil
 
   /**
-   * Override to provide additional rules for rewriting data source plans. Such rules will be
-   * applied after operator optimization rules and before any rules that depend on stats.
+   * Override to provide additional rules for rewriting plans after operator optimization rules and
+   * before any cost-based optimization rules that depend on stats.
    */
-  def dataSourceRewriteRules: Seq[Rule[LogicalPlan]] = Nil
+  def preCBORules: Seq[Rule[LogicalPlan]] = Nil
 
   /**
    * Returns (defaultBatches - (excludedRules - nonExcludableRules)), the rule batches that
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/SparkSessionExtensions.scala b/sql/core/src/main/scala/org/apache/spark/sql/SparkSessionExtensions.scala
index 6952f4bfd056..074906a971b1 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/SparkSessionExtensions.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/SparkSessionExtensions.scala
@@ -40,6 +40,7 @@ import org.apache.spark.sql.execution.{ColumnarRule, SparkPlan}
  * <li>Analyzer Rules.</li>
  * <li>Check Analysis Rules.</li>
  * <li>Optimizer Rules.</li>
+ * <li>Pre CBO Rules.</li>
  * <li>Planning Strategies.</li>
  * <li>Customized Parser.</li>
  * <li>(External) Catalog listeners.</li>
@@ -199,6 +200,21 @@ class SparkSessionExtensions {
     optimizerRules += builder
   }
 
+  private[this] val preCBORules = mutable.Buffer.empty[RuleBuilder]
+
+  private[sql] def buildPreCBORules(session: SparkSession): Seq[Rule[LogicalPlan]] = {
+    preCBORules.map(_.apply(session)).toSeq
+  }
+
+  /**
+   * Inject an optimizer `Rule` builder that rewrites logical plans into the [[SparkSession]].
+   * The injected rules will be executed once after the operator optimization batch and
+   * before any cost-based optimization rules that depend on stats.
+   */
+  def injectPreCBORule(builder: RuleBuilder): Unit = {
+    preCBORules += builder
+  }
+
   private[this] val plannerStrategyBuilders = mutable.Buffer.empty[StrategyBuilder]
 
   private[sql] def buildPlannerStrategies(session: SparkSession): Seq[Strategy] = {
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/internal/BaseSessionStateBuilder.scala b/sql/core/src/main/scala/org/apache/spark/sql/internal/BaseSessionStateBuilder.scala
index c71634f1868e..34b9af12607e 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/internal/BaseSessionStateBuilder.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/internal/BaseSessionStateBuilder.scala
@@ -231,8 +231,8 @@ abstract class BaseSessionStateBuilder(
       override def earlyScanPushDownRules: Seq[Rule[LogicalPlan]] =
         super.earlyScanPushDownRules ++ customEarlyScanPushDownRules
 
-      override def dataSourceRewriteRules: Seq[Rule[LogicalPlan]] =
-        super.dataSourceRewriteRules ++ customDataSourceRewriteRules
+      override def preCBORules: Seq[Rule[LogicalPlan]] =
+        super.preCBORules ++ customPreCBORules
 
       override def extendedOperatorOptimizationRules: Seq[Rule[LogicalPlan]] =
         super.extendedOperatorOptimizationRules ++ customOperatorOptimizationRules
@@ -258,12 +258,14 @@ abstract class BaseSessionStateBuilder(
   protected def customEarlyScanPushDownRules: Seq[Rule[LogicalPlan]] = Nil
 
   /**
-   * Custom rules for rewriting data source plans to add to the Optimizer. Prefer overriding
-   * this instead of creating your own Optimizer.
+   * Custom rules for rewriting plans after operator optimization and before CBO.
+   * Prefer overriding this instead of creating your own Optimizer.
    *
    * Note that this may NOT depend on the `optimizer` function.
    */
-  protected def customDataSourceRewriteRules: Seq[Rule[LogicalPlan]] = Nil
+  protected def customPreCBORules: Seq[Rule[LogicalPlan]] = {
+    extensions.buildPreCBORules(session)
+  }
 
   /**
    * Planner that converts optimized logical plans to physical plans.
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/SparkSessionExtensionSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/SparkSessionExtensionSuite.scala
index 6797dcd34a53..35d251383561 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/SparkSessionExtensionSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/SparkSessionExtensionSuite.scala
@@ -88,6 +88,12 @@ class SparkSessionExtensionSuite extends SparkFunSuite {
     }
   }
 
+  test("SPARK-33621: inject a pre CBO rule") {
+    withSession(Seq(_.injectPreCBORule(MyRule))) { session =>
+      assert(session.sessionState.optimizer.preCBORules.contains(MyRule(session)))
+    }
+  }
+
   test("inject spark planner strategy") {
     withSession(Seq(_.injectPlannerStrategy(MySparkStrategy))) { session =>
       assert(session.sessionState.planner.strategies.contains(MySparkStrategy(session)))