Brad Lidge is 36 years old. In December, when he was still 35, he announced his retirement from professional baseball. He hadn’t been much of a factor since 2010, so in that sense it felt inevitable that Lidge would hang them up. In discussing Lidge’s career, Mike Axisa wrote up the memorable moment that was Albert Pujols taking Lidge deep. Below, in the comments section of that post, some Phillies fans chimed in to say they most remember Lidge for completing the 2008 World Series. Me, I find both of those to be memorable moments, and when it comes to most memorable, that’s entirely subjective. But when I think of Brad Lidge, I don’t think first of Albert Pujols, nor do I think first of Eric Hinske. I don’t think of any one particular moment. I think of the whole sequence of moments that was Lidge’s 2004 season with the Astros.

Craig Kimbrel is coming off an impossible season with the Braves, in which he struck out more than half of the batters he faced. Opposing batters made some sort of contact 61% of the time that they swung. Aroldis Chapman, too, was incredible with the Reds, collecting 122 strikeouts. Opposing batters made some sort of contact 62% of the time that they swung. Going further back now, Eric Gagne was downright unfair as a Dodger in 2003. He won the National League Cy Young, and opposing batters made some sort of contact 56% of the time that they swung.

For Brad Lidge, 2004 was his second full season in the major leagues. Along the way, he turned into the Astros’ closer, and he never looked back. Over 80 regular-season appearances, he logged nearly 95 innings, and he reached 157 strikeouts. Opposing batters made some sort of contact 51% of the time that they swung.

To be more precise, 50.5%, according to Lidge’s FanGraphs player page. We have some plate-discipline data going back to 2002, and since 2002, there have been 3,546 individual pitcher seasons of at least 50 innings. Here’s the contact rate top-five:

Brad Lidge, 2004, 50.5%

Eric Gagne, 2003, 56.2%

Michael Wuertz, 2009, 58.1%

Rudy Seanez, 2005, 58.7%

Brad Lidge, 2005, 59.6%

If you prefer swinging-strike rate instead, here’s that top-five as well:

Brad Lidge, 2004, 25.0%

Eric Gagne, 2003, 22.3%

Eric Gagne, 2004, 21.4%

Eric Gagne, 2002, 20.9%

Brad Lidge, 2005, 20.3%

In 2004, one out of every four Brad Lidge pitches generated a swing and miss. One out of every two swings against a Brad Lidge pitch made contact. It’s not just that 2004 Brad Lidge leads the way; it’s also about the separation between Lidge and the runner-up. The difference between 2004 Lidge and 2003 Gagne by contact rate is nearly six percentage points. Swinging against Brad Lidge in 2004 was essentially a coin flip.

Brad Lidge never repeated what he did in 2004, and Brad Lidge in 2004 didn’t post baseball’s highest-ever strikeout rate. But when I think about unhittability, I think about difficulty of making contact, and that’s where 2004 Lidge is the winner over at least the last 11 years. Consider that, in 2004, the league-average contact rate against relievers was 78%. Armed with a high-90s fastball and a high-80s slider, Lidge allowed batters to make contact with the same frequency with which Barry Bonds reached base in 2001. In this paragraph, a pitcher’s contact rate is compared to a hitter’s on-base percentage.

If you need still more numbers for whatever reason, Lidge missed as many bats in 2004 as Felix Hernandez did in 2010, when he won the American League Cy Young. Felix was a starter and Lidge was a reliever. Lidge missed far more bats in 2004 than AL Cy Young-winner David Price did in 2012. Price was a starter and Lidge was a reliever. Lidge made a mockery of the whole pitcher-batter interaction.

The glimpse I hinted at in the headline — that’s because I was able to find some video. Below are two .gifs of Brad Lidge throwing sliders in 2004. This is all the video I could find of recent baseball’s most unhittable pitcher. It looks a lot like other Brad Lidge videos, but the knowledge that these particular pitches were thrown in 2004 adds a little contextual substance, I think.

That’s clearly a knockout slider, and Lidge threw it nearly half of the time. As a rookie in 2003, Lidge threw 65% fastballs. As a sophomore in 2004, Lidge threw 49% fastballs, and his various numbers went in all the various right directions. Lidge rode his heat and that slider to a season unlike any we’ve seen lately. Other pitchers have the stuff, but they haven’t deployed it with the consistency to match Lidge’s results. For Brad Lidge in 2004, in terms of swings and misses, it just all came together.

Of course, one might blame Lidge’s slider for Lidge’s arm problems. His slider, and his heavy early-career workload. If Brad Lidge pitched differently, Brad Lidge might still be pitching. But now that it’s all over, it’s not like Lidge has a lot to regret, and he’s the author of one incredible season, a season in which batters had as good a chance of whiffing as they had of making contact, in the event they opted to pull the trigger. Nobody’s matched Lidge’s contact rate in 2004. And nobody’s really come all that close.

That second .gif shows Lidge and the Astros locking up the National League Wild Card. Lidge would make seven postseason appearances, striking out 20 of 44 batters faced. Batters attempted 87 swings against Lidge in the playoffs, and about 52% of the time, they made contact. For 2004 Brad Lidge, you could say October was a swing-and-miss slump.