diff --git a/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/baseline_API.json b/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/baseline_API.json
index 4ba3123874d4..acedb3e4b937 100644
--- a/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/baseline_API.json
+++ b/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/baseline_API.json
@@ -36,7 +36,7 @@
     }
   },
   "paths": {
-    "/{resourceUri}/providers/microsoft.insights/baseline/{metricName}": {
+    "/{resourceUri}/providers/Microsoft.Insights/baseline/{metricName}": {
       "get": {
         "tags": [
           "Baseline"
@@ -238,6 +238,15 @@
             "description": "A single high threshold value."
           },
           "description": "The high thresholds of the baseline."
+        },
+        "timestamps": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "format": "date-time",
+            "description": "the timestamp for the baseline value in ISO 8601 format."
+          },
+          "description": "the array of timestamps of the baselines."
         }
       },
       "required": [
diff --git a/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/calculateBaseline_API.json b/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/calculateBaseline_API.json
index e1ce81ced40d..b08c6b762345 100644
--- a/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/calculateBaseline_API.json
+++ b/specification/monitor/resource-manager/Microsoft.Insights/preview/2017-11-01-preview/calculateBaseline_API.json
@@ -195,6 +195,15 @@
             "description": "A single high threshold value."
           },
           "description": "The high thresholds of the baseline."
+        },
+        "timestamps": {
+          "type": "array",
+          "items": {
+            "type": "string",
+            "format": "date-time",
+            "description": "the timestamp for the baseline value in ISO 8601 format."
+          },
+          "description": "the array of timestamps of the baselines."
         }
       },
       "required": [
diff --git a/specification/monitor/resource-manager/readme.md b/specification/monitor/resource-manager/readme.md
index 94b5d4fd9f5e..c557b1c09a33 100644
--- a/specification/monitor/resource-manager/readme.md
+++ b/specification/monitor/resource-manager/readme.md
@@ -618,6 +618,9 @@ directive:
     from: dataCollectionRuleAssociations_API.json
     where: $.paths
     reason: 'Operations API is defined in a separate swagger spec for Microsoft.Insights namespace (https://github.com/Azure/azure-rest-api-specs/blob/master/specification/monitor/resource-manager/Microsoft.Insights/stable/2015-04-01/operations_API.json)'
+  - suppress: R4007
+    from: baseline_API.json
+    reason: 'Updating the error response to the new format would be a breaking change.'
   - suppress: R4007
     from: metricBaselines_API.json
     reason: 'Updating the error response to the new format would be a breaking change.'