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2021 Arizona Diamondbacks Reviews: #23 Joe Mantiply

The Mantiplication Stopped as the Lefty Became a Trusted Option for Torey Lovullo

MLB: Arizona Diamondbacks at Philadelphia Phillies
Joe Mantiply
Kyle Ross-USA TODAY Sports

Rating: 4.36

Age: 30 yrs, 295 Days

2021 Stats: 57 G, 39.2 IP, 3.40 ERA, 2.94 FIP, 10/50 Inherited Runners Scored (20%)

2021 Earnings: Pro rated League Minimum

2022 Status: Pre Arb, On 40 man Roster, Projected Bullpen Spot, 3 Options remaining



Joe Mantiply was drafted three times before he finally signed with a major league club. The first time was by the Mets in the 48th round after his senior year of high school in 2009, but he opted to attend Virginia Tech instead. The Phillies drafted him in 2012 in the 28th round, but he still did not sign, and decided to finish out his collegiate career. After his senior season his draft position improved exactly one round, as the Tigers took him in the 27th in the 2013 draft.

In all he appeared in 42 games for VT, 40 as a starter, going 16-15 with a 3.61 ERA. Notably, even then his trend was to give up a lot of hits, 265 in 242 IP, but only 3 homers.

Despite posting a 2.04 ERA in 12 starts in low A in 2013, the Tigers converted him to reliever in 2014. He made his major league debut as a September callup in 2016 but it didn’t go well. In 5 games, 2.2 IP he allowed 7 hits, a homer and 5 runs. He was exposed to waivers after the season and was picked up by the Yankees. He bounced back and forth between the Yankees and Reds organizations for a couple of years, but missed all of 2018 with TJ surgery. After a 1 game stint in 2019 with the Yankees in the majors he was signed by the Dbacks prior to the 2020 season.

As was covered last year by DBE, things did not go great in his once again limited opportunity in the majors, getting into 4 games and giving up 4 runs. Through that point in his career the near 30 year old lefty had appeared in all of 10 games, with 8 IP and 13 runs allowed. Terms such as “Multiply, and “Mantiplication” would come into use on the AzSnakepit threads. He was DFA’d but cleared waivers, and eventually was signed to a minor league contract prior to the 2021 season.


Mantiply did not make the roster out of spring training and began his season in AAA Reno. He was added to the 40 man roster and called up May 15th. Things started off well enough, as his first two outings were scoreless. However he had a disastrous outing in his 3rd game. Coming into the 7th inning with a a 2-1 lead and a man on he faced 6 batters, retiring just one. He walked a batter, gave up two hits, including a Mookie Betts ground rule double. That was also the game with the Josh Rojas/Pavin Smith popup fiasco with the error charged to Smith. To top things off he hit a batter. 3 runs scored and the D-backs lost 4-2.

He would have 3 more bumpy outings through June 18th, and up to that point in the season, he’d appeared in 15 games throwing 12.1 IP and had a 5.11 ERA , giving up 15 hits and 8 walks.

Joe started to turn things around though, albeit in a 2 steps forward one step back fashion. From June 20 to July 3rd he appeared in 9 games and was personally un-scored upon in all of them, giving up just 1 of 8 inherited runners. But then he gave up runs in back to back games to the Rockies on July 6-7. Still , he was clearly settling in as a go to guy for manager Torey Lovullo. One way you can see this is through his Average Leverage Index. 1 = average pressure, below 1 = low pressure, above 1 = higher pressure. Through July 2nd his aLI was 0.82, or low pressure. From July 3rd on his aLI was 1.46 , or hi pressure

One can use all manner of selective begin and end points to paint the picture of Joe’s season. In recent discussions the pre and post June 18th point has been mentioned. For example 5.11 ERA through 6/18, 2.64 from 6/19 onwards. His longest most effective stretch was probably over his final 17 games, where he allowed just 1 earned run.

The big key for Joe was suppressing homers, (he allowed just 1 all year) which is something he’s done throughout his collegiate and professional career. And he really needs to do that because he gives up a lot of hits, (45 in 39.2 IP) and his walk total of 17 also helped drive his WHIP up to 1.563 on the year.

He induced 6 GBDP in 52 chances, or 12%, which is right around league average 11%. His ground ball rate is not especially high, (46.2%). While his flyball rate was only 27% his line drive rate was 26%. By the way, there is a difference between how Fan Graphs and Baseball Reference record GB/FB rate. FG shows a 1.69 GB/FB rate as they do not include line drives. But BR shows a .86 GB/FB rate as anything NOT on the ground, including LD, are considered balls in the air. The reason I point this out is simply that when you take line drives into account, and despite being a sinker heavy pitcher, Mantiply has a very neutral or average GB/FB ratio.

It’s odd actually. Both his vertical and horizontal movement on his sinker are WAY above average. But it’s off the sinker where hitters have done most of the damage. (.347 BA, .542 Slug against) Scroll down his Statcast Page HERE to see the movement data. But location was clearly an issue, as 100 of his 621 pitches thrown on the year were sinkers in the heart of the zone. Search Report.

One other oddity are his home/road splits

Home: 4.91 ERA, .957 OPS Against in 18.1 IP

Road: 2.11 ERA, .677 OPS Against in 21,1 IP

Don’t ask me why. Small Sample Size Fluke will have to suffice for explanation here. But it probably did skew the perception of Joe’s season for those few fans that actually attended games at Chase Field.


With few other organizational options and barring injury or a catastrophic spring training, expect Joe Mantiply to be a key part of the Diamondbacks bullpen in 2022. If he can reduce the number of location mistakes, he could continue or even improve upon his 2021 success.