We encountered two acute stroke cases with apraxia of speech (AOS) due to left internal border‐zone infarction. Neither case had a lower precentral gyrus lesion in the left frontal lobe. The findings obtained confirmed the relationship between AOS with improvement and damage to the left frontal aslant tract (FAT) in stroke. FAT integrity has potential as a prognostic imaging biomarker of AOS. It is important to visualize the fiber connections of white matter using diffusion tensor tractography, which will predict the outcome of AOS.