diff --git a/api/openapi-spec/swagger.json b/api/openapi-spec/swagger.json
index f0acd1722a1..b4d38cd64d3 100644
--- a/api/openapi-spec/swagger.json
+++ b/api/openapi-spec/swagger.json
@@ -1442,8 +1442,7 @@
         }
       },
       "required": [
-        "replicas",
-        "availableReplicas"
+        "replicas"
       ],
       "type": "object"
     },
diff --git a/api/openapi-spec/v3/apis__apps__v1_openapi.json b/api/openapi-spec/v3/apis__apps__v1_openapi.json
index 9d59e73aba0..8ef9d280796 100644
--- a/api/openapi-spec/v3/apis__apps__v1_openapi.json
+++ b/api/openapi-spec/v3/apis__apps__v1_openapi.json
@@ -1203,8 +1203,7 @@
           }
         },
         "required": [
-          "replicas",
-          "availableReplicas"
+          "replicas"
         ],
         "type": "object"
       },
diff --git a/pkg/apis/apps/types.go b/pkg/apis/apps/types.go
index a86fd4f7dd7..771b2ef23c8 100644
--- a/pkg/apis/apps/types.go
+++ b/pkg/apis/apps/types.go
@@ -257,6 +257,7 @@ type StatefulSetStatus struct {
 
 	// Total number of available pods (ready for at least minReadySeconds) targeted by this statefulset.
 	// This is a beta field and requires enabling StatefulSetMinReadySeconds feature gate.
+	// +optional
 	AvailableReplicas int32
 }
 
diff --git a/pkg/generated/openapi/zz_generated.openapi.go b/pkg/generated/openapi/zz_generated.openapi.go
index 458f3e1b65f..cb739f53580 100644
--- a/pkg/generated/openapi/zz_generated.openapi.go
+++ b/pkg/generated/openapi/zz_generated.openapi.go
@@ -4165,7 +4165,7 @@ func schema_k8sio_api_apps_v1_StatefulSetStatus(ref common.ReferenceCallback) co
 						},
 					},
 				},
-				Required: []string{"replicas", "availableReplicas"},
+				Required: []string{"replicas"},
 			},
 		},
 		Dependencies: []string{
@@ -5273,7 +5273,7 @@ func schema_k8sio_api_apps_v1beta1_StatefulSetStatus(ref common.ReferenceCallbac
 						},
 					},
 				},
-				Required: []string{"replicas", "availableReplicas"},
+				Required: []string{"replicas"},
 			},
 		},
 		Dependencies: []string{
@@ -6930,7 +6930,7 @@ func schema_k8sio_api_apps_v1beta2_StatefulSetStatus(ref common.ReferenceCallbac
 						},
 					},
 				},
-				Required: []string{"replicas", "availableReplicas"},
+				Required: []string{"replicas"},
 			},
 		},
 		Dependencies: []string{
diff --git a/staging/src/k8s.io/api/apps/v1/generated.proto b/staging/src/k8s.io/api/apps/v1/generated.proto
index d46373d92dc..1bdc400b9d2 100644
--- a/staging/src/k8s.io/api/apps/v1/generated.proto
+++ b/staging/src/k8s.io/api/apps/v1/generated.proto
@@ -759,6 +759,7 @@ message StatefulSetStatus {
 
   // Total number of available pods (ready for at least minReadySeconds) targeted by this statefulset.
   // This is a beta field and enabled/disabled by StatefulSetMinReadySeconds feature gate.
+  // +optional
   optional int32 availableReplicas = 11;
 }
 
diff --git a/staging/src/k8s.io/api/apps/v1/types.go b/staging/src/k8s.io/api/apps/v1/types.go
index 74c0ad66d85..28474be7f4f 100644
--- a/staging/src/k8s.io/api/apps/v1/types.go
+++ b/staging/src/k8s.io/api/apps/v1/types.go
@@ -282,6 +282,7 @@ type StatefulSetStatus struct {
 
 	// Total number of available pods (ready for at least minReadySeconds) targeted by this statefulset.
 	// This is a beta field and enabled/disabled by StatefulSetMinReadySeconds feature gate.
+	// +optional
 	AvailableReplicas int32 `json:"availableReplicas" protobuf:"varint,11,opt,name=availableReplicas"`
 }
 
diff --git a/staging/src/k8s.io/api/apps/v1beta1/generated.proto b/staging/src/k8s.io/api/apps/v1beta1/generated.proto
index 7f49e3eb543..53df96ee4de 100644
--- a/staging/src/k8s.io/api/apps/v1beta1/generated.proto
+++ b/staging/src/k8s.io/api/apps/v1beta1/generated.proto
@@ -514,6 +514,7 @@ message StatefulSetStatus {
 
   // Total number of available pods (ready for at least minReadySeconds) targeted by this StatefulSet.
   // This is a beta field and enabled/disabled by StatefulSetMinReadySeconds feature gate.
+  // +optional
   optional int32 availableReplicas = 11;
 }
 
diff --git a/staging/src/k8s.io/api/apps/v1beta1/types.go b/staging/src/k8s.io/api/apps/v1beta1/types.go
index 08a36f5182d..cdc81c956a3 100644
--- a/staging/src/k8s.io/api/apps/v1beta1/types.go
+++ b/staging/src/k8s.io/api/apps/v1beta1/types.go
@@ -321,6 +321,7 @@ type StatefulSetStatus struct {
 
 	// Total number of available pods (ready for at least minReadySeconds) targeted by this StatefulSet.
 	// This is a beta field and enabled/disabled by StatefulSetMinReadySeconds feature gate.
+	// +optional
 	AvailableReplicas int32 `json:"availableReplicas" protobuf:"varint,11,opt,name=availableReplicas"`
 }
 
diff --git a/staging/src/k8s.io/api/apps/v1beta2/generated.proto b/staging/src/k8s.io/api/apps/v1beta2/generated.proto
index f9e3ef7ef51..b5bc8c0cab5 100644
--- a/staging/src/k8s.io/api/apps/v1beta2/generated.proto
+++ b/staging/src/k8s.io/api/apps/v1beta2/generated.proto
@@ -801,6 +801,7 @@ message StatefulSetStatus {
 
   // Total number of available pods (ready for at least minReadySeconds) targeted by this StatefulSet.
   // This is a beta field and enabled/disabled by StatefulSetMinReadySeconds feature gate.
+  // +optional
   optional int32 availableReplicas = 11;
 }
 
diff --git a/staging/src/k8s.io/api/apps/v1beta2/types.go b/staging/src/k8s.io/api/apps/v1beta2/types.go
index a93ef4f9546..6c2448869e7 100644
--- a/staging/src/k8s.io/api/apps/v1beta2/types.go
+++ b/staging/src/k8s.io/api/apps/v1beta2/types.go
@@ -330,6 +330,7 @@ type StatefulSetStatus struct {
 
 	// Total number of available pods (ready for at least minReadySeconds) targeted by this StatefulSet.
 	// This is a beta field and enabled/disabled by StatefulSetMinReadySeconds feature gate.
+	// +optional
 	AvailableReplicas int32 `json:"availableReplicas" protobuf:"varint,11,opt,name=availableReplicas"`
 }