Luis Pena was drafted in 2013, but hasn’t really made a name for himself until the last part of 2017. He’s got a plus slider and plus fastball but still needs more work on his changeup - especially if he wants to be a big league starter. That lack of a 3rd pitch is why many see him as long man out of the pen.
However, in 2017, Pena’s work load greatly increased and he threw 10 games of 6 innings+, including a complete game back in July when he struck out 12 and allowed just 1 earned run.