Selected by the Seattle Mariners in the 28th round of the 2016 MLB Draft out of the University of Arizona, right-handed pitching prospect Nathan Bannister spent his first professional summer on the disabled list, and made his professional debut in 2017 during a full season split between the High-A Modesto Nuts and the Triple-A Tacoma Rainiers. Over 27 games (26 starts) spanning 143.1 innings, Bannister finished 9-7 with a 4.33 ERA, and allowed 153 hits and 21 walks with 117 strikeouts and a .269 opponents’ batting average. That earned him a Pitcher of the Week nod in the California League in late June, and two exceptional starts down the stretch during the Cal League playoffs in September.
Known as ‘Big Game Banni’ by teammates who marvel at his ability to get outs and win games in key situations this early in his career, the righty has an advanced command profile and could eventually project to be a back-end rotation arm thanks to advanced pitchability with some guile and a relatively deep arsenal. Below, you’ll find our full Nathan Bannister scouting report, including game video, tool grades, velocity notes, projection analysis, and more thoughts on the Seattle Mariners pitching prospect.
Nathan Bannister, Seattle Mariners — 2017 Scouting Report
Dates observed in 2017: July 31; September 12
Nathan Bannister Scouting Report — Seattle Mariners — 2017 Game Video
Nathan Bannister Scouting Report — Notes & Analysis
Nathan Bannister doesn’t have above-average stuff, and all smart analysis and good common sense should point the righty to a long relief role considering his lack of velocity and pitch life, but there’s something about his competitiveness and ‘Big Game Banni’ persona that might push past what’s sensible over the next few years. The Seattle Mariners prospect very rarely hurts himself with free passes, works very well — even seems to thrive — with runners on base, and squeezes every last drop out little margin of error in commanding his full arsenal. Bannister will forever be hittable and he must prove in a large sample size in the upper minors that he has the ability to keep better hitters off-balance with weak contact, but the righty is very developed considering his relative lack of pro experience. He could prove to be a relative late-round draft steal for the Seattle Mariners if things go right the next few years. He reminds me a ton of Phillies pitching prospect Thomas Eshelman, though with not quite as good a command profile or as nuanced and tight an arsenal — but Bannister sure isn’t far off. The righty doesn’t have the stuff to be a frontline starter, but there’s a solid chance Nathan Bannister proves himself to be a back-end workhorse as the legend of ‘Big Game Banni’ continues to grow.
Nathan Bannister Scouting Report — Future Projection
After missing his debut pro season with an injury, the Seattle Mariners were aggressive in sending Nathan Bannister right to High-A Modesto in 2017. More than that, they had him pitch 23 innings over four games at Triple-A Tacoma this summer, too — not a full-time gig, but far more than a single spot start in an emergency role. It’s minor, but those level jumps suggest to me the Mariners may internally be high on Bannister’s development, and could sooner rather than later see him as a contributor to the back end of a big league rotation or in middle/long relief. So, let’s go out on a limb here; it may be a small chance, but if things to right with his command profile and pitchability, Nathan Bannister could make his big league debut in 2018 after splitting the season between Double-A Arkansas and Triple-A Tacoma. He must prove his arsenal and gamer mentality will work in the upper minors, of course, but there’s something here that can’t get measured.
Long term, Bannister’s ceiling will come as a #4/5 back-end rotation arm, and he’s got the grittiness and willingness to challenge hitters that he could hit that ceiling, even if for only a few years. More realistically he’ll settle in as a swingman/spot starter type with some long relief work in his future, aided by his ability to throw strikes and his feel for pitching with runners on base. He’s not technically a ‘prospect,’ per se, but Nathan Bannister is certainly a pitcher to track next summer and see whether he’s got the foundation and feel to exceed expectations with the Seattle Mariners before too long.
Overall Future Potential (Future Value): Back-end rotation ceiling with advanced command profile and pitchability; long relief floor with deep arsenal (45)
MLB ETA: 2018