diff --git a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/rescorer/LearnToRankRescorerBuilder.java b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/rescorer/LearnToRankRescorerBuilder.java
index 494af0310953a..bc3348696e959 100644
--- a/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/rescorer/LearnToRankRescorerBuilder.java
+++ b/x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/inference/rescorer/LearnToRankRescorerBuilder.java
@@ -343,8 +343,8 @@ protected void doWriteTo(StreamOutput out) throws IOException {
     protected void doXContent(XContentBuilder builder, Params params) throws IOException {
         builder.startObject(NAME);
         builder.field(MODEL_FIELD.getPreferredName(), modelId);
-        if (params != null) {
-            builder.field(PARAMS_FIELD.getPreferredName(), params);
+        if (this.params != null) {
+            builder.field(PARAMS_FIELD.getPreferredName(), this.params);
         }
         builder.endObject();
     }
diff --git a/x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/inference_rescore.yml b/x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/learn_to_rank_rescorer.yml
similarity index 95%
rename from x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/inference_rescore.yml
rename to x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/learn_to_rank_rescorer.yml
index 824999b3b3008..a0ae4b7c44316 100644
--- a/x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/inference_rescore.yml
+++ b/x-pack/plugin/src/yamlRestTest/resources/rest-api-spec/test/ml/learn_to_rank_rescorer.yml
@@ -146,7 +146,7 @@ setup:
           {
             "rescore": {
               "window_size": 10,
-              "inference": { "model_id": "ltr-model" }
+              "learn_to_rank": { "model_id": "ltr-model" }
             }
           }
   - match: { hits.hits.0._score: 17.0 }
@@ -162,7 +162,7 @@ setup:
             "query": {"term": {"product": "Laptop"}},
             "rescore": {
               "window_size": 10,
-              "inference": { "model_id": "ltr-model" }
+              "learn_to_rank": { "model_id": "ltr-model" }
             }
           }
   - match: { hits.hits.0._score: 6.0 }
@@ -182,7 +182,7 @@ setup:
           {
             "rescore": {
               "window_size": 2,
-              "inference": { "model_id": "ltr-model" }
+              "learn_to_rank": { "model_id": "ltr-model" }
             }
           }
   - match: { hits.hits.0._score: 17.0 }
@@ -209,7 +209,7 @@ setup:
             },
             {
               "window_size": 3,
-              "inference": { "model_id": "ltr-model" }
+              "learn_to_rank": { "model_id": "ltr-model" }
             },
             {
               "window_size": 2,
@@ -232,7 +232,7 @@ setup:
           {
             "rescore": {
               "window_size": 10,
-              "inference": { "model_id": "ltr-missing" }
+              "learn_to_rank": { "model_id": "ltr-missing" }
             }
           }
 ---
@@ -245,7 +245,7 @@ setup:
             "query": {"term": {"product": "Speaker"}},
             "rescore": {
               "window_size": 10,
-              "inference": { "model_id": "ltr-model" }
+              "learn_to_rank": { "model_id": "ltr-model" }
             }
           }
   - length: { hits.hits: 0 }