Marcus Semien and the Texas Rangers play George Springer and the Toronto Blue Jays at Globe Life Field on Thursday. First pitch is at 2:35 p.m. ET.The Rangers have a 4.37 team ERA that ranks 25th

Texas Rangers top prospect Kumar Rocker struck out seven and allowed one run in four innings against the Seattle Mariners in his MLB debut Thursday night.

ARLINGTON — Here’s the deal: Statcast classifies Kumar Rocker’s nasty breaking pitch as a slider. He calls it a curveball and a “slider at times.” It was the most effective tool in his Texas Rangers debut last Thursday against the Seattle Mariners and secured five of his seven strikeouts.