diff --git a/src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.ts b/src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.ts
index a53e06cdea0a..9144e505133c 100644
--- a/src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.ts
+++ b/src/plugins/data/server/index_patterns/fetcher/index_patterns_fetcher.ts
@@ -28,7 +28,7 @@
  * under the License.
  */
 
-import { LegacyAPICaller, OpenSearchClient } from 'opensearch-dashboards/server';
+import { LegacyAPICaller } from 'opensearch-dashboards/server';
 
 import { getFieldCapabilities, resolveTimePattern, createNoMatchingIndicesError } from './lib';
 
@@ -48,9 +48,9 @@ interface FieldSubType {
 }
 
 export class IndexPatternsFetcher {
-  private _callDataCluster: LegacyAPICaller | OpenSearchClient;
+  private _callDataCluster: LegacyAPICaller;
 
-  constructor(callDataCluster: LegacyAPICaller | OpenSearchClient) {
+  constructor(callDataCluster: LegacyAPICaller) {
     this._callDataCluster = callDataCluster;
   }
 
diff --git a/src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_capabilities.ts b/src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_capabilities.ts
index 57d59ce5a486..0aee1222a361 100644
--- a/src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_capabilities.ts
+++ b/src/plugins/data/server/index_patterns/fetcher/lib/field_capabilities/field_capabilities.ts
@@ -30,7 +30,7 @@
 
 import { defaults, keyBy, sortBy } from 'lodash';
 
-import { LegacyAPICaller, OpenSearchClient } from 'opensearch-dashboards/server';
+import { LegacyAPICaller } from 'opensearch-dashboards/server';
 import { callFieldCapsApi } from '../opensearch_api';
 import { FieldCapsResponse, readFieldCapsResponse } from './field_caps_response';
 import { mergeOverrides } from './overrides';
@@ -47,7 +47,7 @@ import { FieldDescriptor } from '../../index_patterns_fetcher';
  *  @return {Promise<Array<FieldDescriptor>>}
  */
 export async function getFieldCapabilities(
-  callCluster: LegacyAPICaller | OpenSearchClient,
+  callCluster: LegacyAPICaller,
   indices: string | string[] = [],
   metaFields: string[] = [],
   fieldCapsOptions?: { allowNoIndices: boolean }
diff --git a/src/plugins/data/server/index_patterns/fetcher/lib/opensearch_api.ts b/src/plugins/data/server/index_patterns/fetcher/lib/opensearch_api.ts
index 5fcbb01ce07a..0a33e51b1018 100644
--- a/src/plugins/data/server/index_patterns/fetcher/lib/opensearch_api.ts
+++ b/src/plugins/data/server/index_patterns/fetcher/lib/opensearch_api.ts
@@ -57,23 +57,10 @@ export interface IndexAliasResponse {
  *  @return {Promise<IndexAliasResponse>}
  */
 export async function callIndexAliasApi(
-  callCluster: LegacyAPICaller | OpenSearchClient,
+  callCluster: LegacyAPICaller,
   indices: string[] | string
 ): Promise<IndicesAliasResponse> {
   try {
-    // This approach of identify between OpenSearchClient vs LegacyAPICaller
-    // will be deprecated after support data client with legacy client
-    // https://github.com/opensearch-project/OpenSearch-Dashboards/issues/2133
-    if ('transport' in callCluster) {
-      return (
-        await callCluster.indices.getAlias({
-          index: indices,
-          ignore_unavailable: true,
-          allow_no_indices: true,
-        })
-      ).body as IndicesAliasResponse;
-    }
-
     return (await callCluster('indices.getAlias', {
       index: indices,
       ignoreUnavailable: true,
@@ -97,25 +84,11 @@ export async function callIndexAliasApi(
  *  @return {Promise<FieldCapsResponse>}
  */
 export async function callFieldCapsApi(
-  callCluster: LegacyAPICaller | OpenSearchClient,
+  callCluster: LegacyAPICaller,
   indices: string[] | string,
   fieldCapsOptions: { allowNoIndices: boolean } = { allowNoIndices: false }
 ) {
   try {
-    // This approach of identify between OpenSearchClient vs LegacyAPICaller
-    // will be deprecated after support data client with legacy client
-    // https://github.com/opensearch-project/OpenSearch-Dashboards/issues/2133
-    if ('transport' in callCluster) {
-      return (
-        await callCluster.fieldCaps({
-          index: indices,
-          fields: '*',
-          ignore_unavailable: true,
-          allow_no_indices: fieldCapsOptions.allowNoIndices,
-        })
-      ).body as FieldCapsResponse;
-    }
-
     return (await callCluster('fieldCaps', {
       index: indices,
       fields: '*',
diff --git a/src/plugins/data/server/index_patterns/fetcher/lib/resolve_time_pattern.ts b/src/plugins/data/server/index_patterns/fetcher/lib/resolve_time_pattern.ts
index 7b19ff78646f..c1ef0074a1d6 100644
--- a/src/plugins/data/server/index_patterns/fetcher/lib/resolve_time_pattern.ts
+++ b/src/plugins/data/server/index_patterns/fetcher/lib/resolve_time_pattern.ts
@@ -47,10 +47,7 @@ import { callIndexAliasApi, IndicesAliasResponse } from './opensearch_api';
  *                            and the indices that actually match the time
  *                            pattern (matches);
  */
-export async function resolveTimePattern(
-  callCluster: LegacyAPICaller | OpenSearchClient,
-  timePattern: string
-) {
+export async function resolveTimePattern(callCluster: LegacyAPICaller, timePattern: string) {
   const aliases = await callIndexAliasApi(callCluster, timePatternToWildcard(timePattern));
 
   const allIndexDetails = chain<IndicesAliasResponse>(aliases)