Dallas Cowboys quarterback Dak Prescott is out of a walking boot following a minor sprain of his right foot, ESPN and NFL Network reported on Thursday.A photo posted on social media on Wednesday showed Prescott in a walking boot in Cabo San Lucas, but it’s unclear how or when the injury occurred. The Cowboys haven’t held an organized workout since June 5.Per the reports, Prescott is expected to be ready to practice when the Cowboys open training camp on July 25.