Complex sentence: While Jenrry Mejia was permanently banned by Rob Manfred in February 2016 for third positive test for performance-enhancing drugs, he will be eligible to apply for reinstatement until 2017, although he won't be eligible to pitch until 2018 at the earliest.
Split into simpler sentences: While Jenrry Mejia was permanently banned by Rob Manfred in February 2016 for third positive test for performance-enhancing drugs, he will be eligible to apply for reinstatement in 2017. Should he be reinstated, Mejia will not be eligible to pitch until 2018 at the earliest.