If there’s an area more invested in Thursday night’s Rangers-Mariners game in Seattle than people in Dallas-Fort Worth and Seattle, it’s likely Nashville. Former Vanderbilt star Kumar Rocker is making his MLB debut after being the No. 3 overall pick of Texas in 2022. Supporting him from the dugout will be a familiar face in Jack Leiter, his partner in crime with the Commodores. Leiter and Rocker dominated the college baseball world together. It’s as deadly of a weekend rotation as we have seen in the sport recently. Never would have they imagined pitching together on the same big league staff …