diff --git a/vllm/model_executor/sampling_metadata.py b/vllm/model_executor/sampling_metadata.py
index 84f35f75a0c32..1df8f84ed4093 100644
--- a/vllm/model_executor/sampling_metadata.py
+++ b/vllm/model_executor/sampling_metadata.py
@@ -454,6 +454,7 @@ def from_sampling_metadata(
         if do_penalties:
             for seq_group in sampling_metadata.seq_groups:
                 seq_ids = seq_group.seq_ids
+                sampling_params = seq_group.sampling_params
                 if (seq_group.is_prompt
                         and sampling_params.prompt_logprobs is not None):
                     prefill_len = len(seq_group.prompt_logprob_indices)