diff --git a/internal/worker_versioning_rules.go b/internal/worker_versioning_rules.go
index 80a2b11cb..d6e5da12b 100644
--- a/internal/worker_versioning_rules.go
+++ b/internal/worker_versioning_rules.go
@@ -308,10 +308,13 @@ func versioningAssignmentRuleToProto(rule *VersioningAssignmentRule) *taskqueuep
 
 	switch r := rule.Ramp.(type) {
 	case *VersioningRampByPercentage:
-		result.Ramp = &taskqueuepb.BuildIdAssignmentRule_PercentageRamp{
-			PercentageRamp: &taskqueuepb.RampByPercentage{
-				RampPercentage: r.Percentage,
-			},
+		// Ramp is optional, checking for typed `nil`
+		if r != nil {
+			result.Ramp = &taskqueuepb.BuildIdAssignmentRule_PercentageRamp{
+				PercentageRamp: &taskqueuepb.RampByPercentage{
+					RampPercentage: r.Percentage,
+				},
+			}
 		}
 	}
 
@@ -419,8 +422,10 @@ func (r *VersioningAssignmentRule) validateRule() error {
 	}
 	switch ramp := r.Ramp.(type) {
 	case *VersioningRampByPercentage:
-		if err := ramp.validateRamp(); err != nil {
-			return err
+		if ramp != nil {
+			if err := ramp.validateRamp(); err != nil {
+				return err
+			}
 		}
 		// Ramp is optional, defaults to "nothing to validate"
 	}
diff --git a/internal/worker_versioning_rules_test.go b/internal/worker_versioning_rules_test.go
index 141b624f2..be0ff903a 100644
--- a/internal/worker_versioning_rules_test.go
+++ b/internal/worker_versioning_rules_test.go
@@ -139,3 +139,20 @@ func Test_VersioningIntent(t *testing.T) {
 		})
 	}
 }
+
+func Test_WorkerVersioningRules_typed_nil(t *testing.T) {
+	var ramp *VersioningRampByPercentage
+
+	u := UpdateWorkerVersioningRulesOptions{
+		TaskQueue: "myQueue",
+		Operation: &VersioningOperationInsertAssignmentRule{
+			RuleIndex: 0,
+			Rule: VersioningAssignmentRule{
+				TargetBuildID: "2.0",
+				Ramp:          ramp,
+			},
+		},
+	}
+	_, err := u.validateAndConvertToProto("my_namespace")
+	assert.NoError(t, err)
+}