diff --git a/fiftyone/utils/eval/detection.py b/fiftyone/utils/eval/detection.py
index 32aef9af2f..270a7d3b25 100644
--- a/fiftyone/utils/eval/detection.py
+++ b/fiftyone/utils/eval/detection.py
@@ -64,7 +64,13 @@ def spin():
 
 
 def _evaluate_detections_bulk(
-    _samples, gt_field, pred_field, eval_method, eval_key, progress=True
+    _samples,
+    gt_field,
+    pred_field,
+    eval_method,
+    eval_key,
+    progress=True,
+    save=True,
 ):
     matches = []
     id_field = "id"
@@ -75,6 +81,7 @@ def _evaluate_detections_bulk(
 
     decorated_func = spinner_decorator(enabled=True)(_samples.values)
 
+    # might want to fetch batches of data instead of the whole collection
     ids, ground_truths, predictions = decorated_func(
         [id_field, gt_field, pred_field]
     )
@@ -97,9 +104,10 @@ def _evaluate_detections_bulk(
         matches.extend(doc_matches)
         tp, fp, fn = _tally_matches(doc_matches)
 
-        sample_updates["sample_tp"][id] = tp
-        sample_updates["sample_fp"][id] = fp
-        sample_updates["sample_fn"][id] = fn
+        if save:
+            sample_updates["sample_tp"][id] = tp
+            sample_updates["sample_fp"][id] = fp
+            sample_updates["sample_fn"][id] = fn
         pb.update()
 
     docs = (ids, ground_truths, predictions)
@@ -284,6 +292,7 @@ def evaluate_detections(
             eval_method,
             eval_key,
             progress=progress,
+            save=save,
         )
         end_time = time.time()
         logger.info(