Consider Mason Miller the latest evolution of the flame-throwing, fire-breathing relief pitcher, from Dick Radatz to Goose Gossage to Rob Dibble to Billy Wagner to Craig Kimbrel and Aroldis Chapman. Pitching in one-inning bursts of thrilling 101 mph fastballs, Miller had a streak of 37⅓ scoreless innings going back to last season until he allowed two runs last week while closing out a win for the San Diego Padres over the Chicago Cubs.
Even then, it was a bit of a fluke, as the Cubs' rally began with a 49.5 mph roller down the third-base line that might have been a foul ball. Two more base hits, a groundout and a wild pitch followed, and Miller saw his ERA climb from 0.00 all the way to 1.26 and his batting average allowed skyrocket from .071 to ... .125.
Despite that little blip, Miller's domination since the Padres acquired him from the Athletics last season has put his name in the conversation about some of the best reliever seasons we've ever seen.
Let's find out how true that statement is: Are we watching the best relief season in MLB history? Here's how Miller's astounding early numbers stack up to all-time reliever records -- and how many new marks Miller could set this season.
(For all records, we're using a minimum of 50 innings pitched in a season.)
Lowest batting average allowed
Current record: .113 (Kirby Yates, 2024 Texas Rangers)
Miller, 2026: .121
Record in play? Yes
I speculated before the season that a sub-.100 average allowed could be in play with Miller. Since Aug. 6 of last season, including two postseason appearances, he has allowed an .081 average. As his outing against the Cubs showed, however, it takes only a couple of soft hits here and there to make that under-.100 average an even more difficult task.
Yates' 2024 season flew under the radar at the time as he allowed just 23 hits in 61⅔ innings. He finished strong, allowing four hits in his final 22 innings. According to Statcast, Yates' expected average allowed was .146, so he allowed about seven fewer hits than expected based on his contact quality.
Certainly, the fewer balls in play that Miller allows, the better his odds are of topping Yates' average. That means a lot of strikeouts ...
Strikeout rate
Current record: 52.5% (Aroldis Chapman, 2014 Cincinnati Reds)
Miller, 2026: 55.7%
Record in play? Yes
Three relievers have struck out 50% of the batters they faced in a season: Chapman in 2014, Kimbrel in 2012 (50.2%) and Edwin Diaz in 2022 (50.2%). Chapman was absolutely dominant in 2014, throwing 494 pitches at 100-plus mph -- and batters put just 39 of them in play.
Chapman threw his fastball nearly 69% of the time that season, and then often went to his slider with two strikes, but Miller's approach is much different. He throws his slider 52.6% of the time compared with 40% for his triple-digit heater. His swing-and-miss rate on his fastball is a little higher than Chapman's rate in 2014 -- 44.6% to 41% -- but Miller has generated an absurd 73.6% whiff rate with his slider, so his overall swing-and-miss rate is much higher than Chapman's, 57.8% to 45.4%.
That should give Miller a good chance at the record, and after a blip in which he fanned just two of 16 batters faced, he's back on track with five strikeouts in his past two appearances. Batters had stopped swinging as much at the slider, so Miller adjusted and threw his fastball more often.
Strikeouts in a season
Current record: 181 (Dick Radatz, 1964 Boston Red Sox)
Miller's 2026 pace: 153
Record in play? No
Radatz was a 6-foot-6 mountain of a man nicknamed "The Monster." He threw from a whippy sidearm motion like Don Drysdale and had a dominant three-year run from 1962 to 1964 when he went 40-21 with a 2.17 ERA as a reliever -- while averaging 138 innings per season, including 157 in 1964. Radatz would blame his burnout on adding a sinker in 1965 (at the suggestion of Ted Williams), saying, "I changed my arm position ... and it was all downhill from there."
Miller, of course, won't approach 100 innings, let alone 150. He pitched 61⅔ innings last year, racking up 104 strikeouts, an impressive 15.2 K's per nine. Maybe he can go for the highest sub-100-inning mark of 157, set by Brad Lidge with the Houston Astros in 2004. Josh Hader fanned 143 in 81⅓ innings in 2018, a top-10 mark all time.
Lowest OPS allowed
Current record: .358 (Craig Kimbrel, 2012 Atlanta Braves)
Miller, 2026: .285
Record in play? Yes
The key here is not allowing extra-base hits or surrendering too many walks. Kimbrel allowed a .126 average in 2012 and just four extra-base hits, although three of them were home runs. He walked just 14 batters in 62⅔ innings, the best control season of his career.
So far, so good for Miller. All seven hits he has allowed have been singles, and he has cut his walk rate from 4.1 walks per nine innings in 2025 to 1.6 so far in 2026. Miller did allow five home runs in 2025 -- all off his fastball. Four of them came on first-pitch fastballs, so there was a definite pattern there, which Miller has adjusted to by throwing more first-pitch sliders. It's working so far.
Lowest ERA
Current record: 0.54 (Zack Britton, 2016 Baltimore Orioles)
Miller, 2026: 1.04
Record in play? Probably not
This will be a tough one. If Miller pitches the same 61⅔ innings as last season, he can allow only three earned runs; four earned runs in those innings would leave him with a 0.58 ERA. Britton allowed four earned runs in 67 innings (and three unearned runs, which all came in the same outing). His key: one home run allowed and an .085 batting average allowed with runners in scoring position. Miller has no margin of error here.
One bloop and a blast and this looks out of reach.
Most saves
Current record: 62 (Francisco Rodriguez, 2008 Los Angeles Angels)
Miller's 2026 pace: 50
Record in play? No
Rodriguez's saves record is one of the more underrated records in the sport as he has a sizable five-save gap over the No. 2 guys, Edwin Diaz for the Seattle Mariners in 2018 and Bobby Thigpen for the Chicago White Sox in 1990. Rodriguez's season was interesting as he made 76 appearances but pitched just 68⅓ innings -- so the innings total is reasonable by 2026 standards, but he had five one-out saves and three two-out saves, as Angels manager Mike Scioscia often brought Rodriguez into games after danger struck in the ninth. In fact, the Angels had a lot of those games that year: Rodriguez was hardly perfect, blowing seven save chances, so his sheer volume of opportunity is hard to match.
He also pitched three days in a row on five separate occasions -- something managers are increasingly reluctant to do these days. Miller pitched three straight days just once last season and hasn't done so yet in 2026. Jason Adam and Adrian Morejon each have a save for the Padres, as manager Craig Stammen will hand a save opportunity to another reliever in order to avoid using Miller three straight days.
Most saves (no blown)
Current record: 55-for-55 (Eric Gagne, 2003 Los Angeles Dodgers)
Miller, 2026: 11-for-11 in saves
Record in play? Maybe?
Miller might not get that many opportunities, but here's what IS in play: a perfect season. Gagne lost three games that year (and blew the save while picking up the loss in the All-Star Game, if you want to count that).
Three other relievers have saved at least 30 games without blowing a save: Jose Valverde went 49-for-49 for the Detroit Tigers in 2011, Baltimore's Britton was 47-for-47 in 2016 and Lidge was 41-for-41 for the Philadelphia Phillies in 2008. Lidge, however, is the only one with a perfect season: He went 2-0 and was also 7-for-7 in save chances in the postseason.
Alas ... Lidge ALSO lost the All-Star Game that year.
OK, maybe that doesn't count, but what makes going perfect in 2026 more difficult is the free runner in extra innings. It's easy to blow a save or lose a game without even giving up a hit. One of Miller's two losses last year came in this fashion -- not giving up a hit but walking in the winning run with the bases loaded.
Highest WAR
Current record: 8.2 (Goose Gossage, 1975 White Sox) / 5.2 (Bruce Sutter, 1977 Cubs)
Miller's 2026 pace: 4.5 (Baseball-Reference) / 5.4 (FanGraphs)
Record in play? It's complicated
Since Baseball-Reference and FanGraphs calculate their pitcher WAR much differently, one of these is out of reach, but the other is in play. Gossage pitched 141⅔ innings, going 9-8 with 26 saves and a 1.84 ERA. Baseball-Reference also factors leverage into its reliever WAR, and Gossage pitched a lot of high-leverage innings that year.
The highest bWAR for a sub-100-inning reliever is Jonathan Papelbon's 5.0 for the Red Sox in 2006, when he had a 0.92 ERA and 35 saves in 68⅓ innings.
FanGraphs WAR focuses on hits, walks and home runs -- and Miller has dominated those categories so far, posting 1.2 fWAR through the Padres' first 36 games, putting him on a record pace even though he won't come close to the 107 innings that Sutter pitched in 1977.