Thoracic Outlet Syndrome Fells Archer

If the 2020 season does happen — and right now, that’s an open question — it will be without Chris Archer. The Pirates announced on Wednesday that the 31-year-old righty underwent surgery to correct for thoracic outlet syndrome, ruling him out for whatever transpires this season, and perhaps ending his time in Pittsburgh given his contract situation. Given the track record of pitchers who have undergone the procedure, we can only hope that this doesn’t mark the end of the two-time All-Star’s run as an effective pitcher.

As I’ve written before, thoracic outlet syndrome is caused by a compression of the nerves and/or blood vessels somewhere between the neck and the armpit. Symptoms commonly include numbness or tingling in the fingers and hands, or fatigue or weakness that doesn’t go away with physical therapy and rest. Pitchers tend to be particularly vulnerable to TOS because of their repetitive overhand movements and the way their arm muscles build up. The condition is generally remedied by the removal of a cervical rib and two small scalene muscles.

Archer, whom the Pirates acquired from the Rays on July 31, 2018 in exchange for outfielder Austin Meadows and pitchers Tyler Glasnow and Shane Baz (the latter as a player to be named later) — a steal of a deal for Tampa Bay, the way things have gone — endured the worst season of his eight-year career in 2019. Though he struck out a respectable 27.2% of hitters faced, his walk and home run rates jumped significantly from their 2018 levels, the former from 7.7% to 10.5%, the latter from 1.15 per nine to 1.88. Both of those were career highs, as were his 5.19 ERA and 5.02 FIP, which were respectively 20% and 13% worse than league average. Per Pitch Info, his average four-seam fastball velocity fell a full tick from 2018 (95.3 mph to 94.3 mph) and was down 1.5 mph relative to ’17 and 1.9 mph relative to ’15.

Amid that grim litany, Archer actually pitched significantly better after the All-Star break than before:

Chris Archer 2019 Splits
1st Half 78.2 2.29 25.3% 11.8% 13.5% 88.7 .383 5.49 5.92
2nd Half 41.0 1.10 30.9% 7.9% 23.0% 86.7 .277 4.61 3.29
SOURCE: Baseball Savant

Unfortunately, his renaissance was cut short due to injuries. Having already served 18 days for right thumb inflammation in late April and early May, he left his August 20 start after one inning due to right shoulder inflammation. Though he began rehabbing towards a return, he was shut down for the season in mid-September. After the season, the Pirates picked up his $9 million option and termed him “healthy and full systems go” as of mid-December, but he was scratched from his first scheduled spring start on February 24 due to neck discomfort. He made his spring debut on March 6 with four strikeouts in a pair of scoreless innings against the Blue Jays, but didn’t get to pitch again before the COVID-19 shutdown.

In a conference call with reporters on Wednesday, general manager Ben Cherington and director of sports medicine Todd Tomczyk noted that Archer had indicated further neck discomfort before the closure of camp but remained on a monitored throwing program after the closure. He experienced some symptoms common to pitchers who experience thoracic outlet syndrome but not all of them, and not immediately after throwing; sometimes, it was hours or days later. Via’s Adam Berry:

“What is consistent with TOS is the inconsistencies, so that’s what makes it sometimes challenging to make a clear-cut diagnosis,” Tomczyk said. “But Chris is and was very diligent with marking down what he felt, when he felt it, to help himself and help us and the physicians really pin down the correct diagnosis so we could help him move forward.”

Doctors determined that his throwing shoulder and elbow were structurally sound, Tomczyk said, and experts initially ruled out the possibility that he had thoracic outlet syndrome. However, Tomczyk noted that it can take time for doctors to definitively diagnosis the syndrome; reliever Nick Burdi visited multiple doctors before having a similar surgery last year, for instance.

Archer won’t be able to pitch this year, leaving the Pirates to decide on how to handle his $11 million option for 2021; the buyout is $250,000. For the tight-fisted franchise whose estimated 2020 payroll is only $61 million, that seems like a long shot, even given his upside. “We won’t have games to evaluate, but there will be other information that we have at that time that we don’t have now. So we’ll just want to take all the time we have,” said Cherington.

Complicating matters for the Pirates and Archer is the sad fact that unlike Tommy John surgery, the range of outcomes is quite wide when it comes to pitchers who have undergone surgery to correct TOS, and there aren’t a ton of success stories. Updating the data I pulled together for my May 2018 piece on Phil Hughes:

Pitchers Who Underwent Thoracic Outlet Syndrome Surgery
Pitcher Yr surgery Age Pre ERA- FIP- Post ERA- FIP- ERA- dif FIP- dif
Nick Burdi* 2019 26 10.0 256 83 0.0 N/A N/A N/A N/A
Drew VerHagen* 2016 25 50.1 103 111 148.2 120 107 17 -4
Alex Cobb* 2011 23 52.2 88 91 812.0 95 98 7 7
Nate Adcock 2014 26 95.0 91 109 28.0 138 153 47 44
Mike Foltynewicz* 2015 23 105.1 146 133 577.1 94 99 -52 -34
John Rheinecker 2008 28 121.0 120 108 0.0 N/A N/A N/A N/A
Matt Harrison 2009 24 147.0 125 114 521.1 87 98 -38 -16
Carter Capps 2017 26 147.2 110 82 0.0 N/A N/A N/A N/A
Nick Tepesch* 2015 25 219.0 111 118 19.2 150 192 39 74
Aaron Cook 2004 25 256.1 105 102 1150.0 92 99 -13 -3
Daniel Bard 2014 29 257.1 85 97 0.0 N/A N/A N/A N/A
Vince Velasquez* 2017 26 258.2 107 100 264.0 116 101 9 1
Nate Karns* 2017 29 310.2 109 108 5.1 0 75 -109 -33
Mike Adams 2012 34 363.2 56 71 43.2 95 111 39 40
Matt Harvey* 2016 27 519.2 79 72 307.1 142 128 63 56
Jaime García 2014 28 594.2 92 89 540.1 102 100 8 11
Noah Lowry 2009 28 618.1 92 102 0.0 N/A N/A N/A N/A
Tyson Ross* 2016 29 670.2 98 89 234 122 118 24 29
Clayton Richard* 2014 30 773.1 114 113 511.1 117 107 3 -6
Chris Young 2013 34 890.2 92 101 348.1 107 135 15 34
Luke Hochevar 2016 32 929.1 117 104 0.0 N/A N/A N/A N/A
Kip Wells 2006 28 983.2 100 104 354.2 132 116 32 12
Jeremy Bonderman 2008 25 994.2 107 93 236.1 139 127 32 34
Shaun Marcum 2013 31 995.0 94 100 35.0 132 143 38 43
Phil Hughes 2016 30 1204.2 106 98 86.1 142 137 36 39
Chris Archer* 2020 31 1235.0 96 90 0.0 N/A N/A N/A N/A
Josh Beckett 2013 33 1935.1 91 89 115.2 83 119 -8 30
Kenny Rogers 2001 36 2049.1 92 95 1253.1 94 101 2 6
Chris Carpenter 2012 37 2207.1 86 88 17.0 96 106 10 18
Pitchers ranked by pre-surgery innings totals. Negative ERA-/FIP- differentials indicate improvement with respect to park-adjusted league average

I’ve made the table sortable, so you can see how things shake out in a variety of ways. It’s worth noting that Archer is in the oldest quartile here, and is fourth in pre-surgical innings; the three pitchers ahead of him ranged from 17 post-surgical innings to 1,253.1, which isn’t much help in terms of forecasting. More helpful was sorting the pitchers into three buckets based on the age at which they had the surgery:

Thoracic Outlet Surgery Outcomes by Age
Age # Pre IP ERA- FIP- Post IP ERA- FIP- ERA- dif FIP- dif NR
22-26 11 212 110 100 376 99 102 -10 1 18%
27-30 8 509 95 95 180 120 113 30 21 38%
31-older 9 1261 95 95 268 102 110 8 15 11%
NR= no return to MLB.

The youngest group of pitchers fared the best afterwards, throwing more post-surgical innings than pre-surgical ones, and seeing some improvement in performance. The oldest bunch, the group of which Archer will be part, saw some decline, but the group in the middle was a wasteland even apart from the fact that three of its eight pitchers never made it back to the majors. Nearly half the innings of that cohort belong to Harvey and Wells, both of whom served as piñatas for major league hitters following surgery. Their outsized effect on that group should serve as a reminder that these are small sample sizes, and so an extreme performance here or there can skew the numbers. On that note, if I remove Rogers from the oldest group simply to note the effect his success has on the overall numbers, the innings averages drop to 1,162 pre-surgery and 144 post-surgery; while the ERA- and FIP- for the former remain the same, those for the latter jump to 112 and 120 — roughly as (in)effective as the middle group.

Admittedly, this is a pretty crude analysis that’s only boiling things down to run prevention and its components. It may well be more instructive to look more closely at things like pre-surgical velocity and spin rate, at least for the more recent pitchers who have that data, but that comes at the expense of sample size. It’s possible that Archer’s ability to throw in the mid-90s increases his chances of a successful return compared to a pitcher like Hughes, whose velo was in the low 90s when he went under the knife. Maybe it’s significant that Archer was pitching well just prior to being sidelined, rather than enduring a grim slog towards the injured list. Perhaps the variations in type of TOS — neurogenic (roughly three-quarters of cases, including Archer’s), venous, or arterial — are significant when it comes to post-surgical outlook, though we simply don’t have classifications for most of the pitchers above. There’s a lot we don’t know, however, and so we can only hope that the comeback of a pitcher who once rated among the game’s most promising goes well.

Brooklyn-based Jay Jaffe is a senior writer for FanGraphs, the author of The Cooperstown Casebook (Thomas Dunne Books, 2017) and the creator of the JAWS (Jaffe WAR Score) metric for Hall of Fame analysis. He founded the Futility Infielder website (2001), was a columnist for Baseball Prospectus (2005-2012) and a contributing writer for Sports Illustrated (2012-2018). He has been a recurring guest on MLB Network and a member of the BBWAA since 2011, and a Hall of Fame voter since 2021. Follow him on Twitter @jay_jaffe... and BlueSky

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3 years ago

Kind of feels like the end for him. It’s going to take a ton of time for him to rehab, the surgery outcomes are not optimistic, and he was already having trouble finding consistency.

3 years ago
Reply to  sadtrombone

Probably the end of returning to ace-status, but I suspect that Ray Searage was responsible for 80% or more of his struggles in Pittsburgh (it’s no coincidence that Archer’s K/9 dropped immediately upon getting to Pittsburgh while Morton, Cole, and Glasnow are improved immediately). Even looking at the chart, if he suffers the expected drop in performance, assuming most of his pre-injury problems were because Searage was again trying to stick a round peg in a square hole, he could be an average MLB pitcher for a little while longer. He’s a great athlete which should help him in his recovery and maybe help him get some velo back if he uses his legs more in his delivery.