פירוש על עבודה זרה 71:5

Rav discounts Shmuel’s statement because it is attributed to R. Simlai who is from Lod, and in Lod they are not respectful of rabbinic statements.
Shmuel boldly offers to send for Simlai to check to see if his statement is accurate. Rav becomes embarrassed. He does not want to criticize Simlai to his face.