The Yankees may be poised to turn to their top pitching prospect for some bullpen help down the stretch. A source tells Dan Martin of the New York Post that 22-year-old left-hander Justus Sheffield will soon be called up and work as a reliever for the Yankees. 

The essentials on Sheffield ... 

Justus Sheffield, LHP, Yankees

Age: 22
Drafted: 2014 first round (31st overall, by Indians) out of Tullahoma HS in Tennessee
Signing bonus: $1.6 million
Acquired: From Indians as part of July 2016 Andrew Miller trade
MLB.com 2018 prospect ranking: No. 48 overall
Career stats: 3.08 ERA, 2.76 K/BB ratio in 103 games (94 starts) across parts of five minor-league seasons.
2018 stats: 2.48 ERA, 2.46 K/BB ratio in 25 games (20 starts) at the Double-A and Triple-A levels.
Rapid-fire scouting report: Mid-90s velocity, plus fastball-slider combo. Changeup needs some refinement in order for him to stick in rotation, but should be a bullpen weapon regardless. Relatively clean health history and sound mechanics.

As noted, Sheffield for now will reportedly work out of Aaron Boone's bullpen, potentially as the second lefty behind Zach Britton. Given that Sheffield has worked primarily as a starter, he may also be able to give Boone some multi-inning outings over the final two weeks and thus afford some of those core reliever's some rest. 

The Yankees are all but out of the AL East race but are still trying to fend off the Athletics for the right to host the AL Wild Card Game. As such, don't be surprised if Sheffield gets a couple of low-leverage appearances before Boone inserts him into a pressure situation. 

Whatever the case, the Yankees have added another live arm to their already deep bullpen.