Don’t test Yadier Molina.

For nearly two decades, Major League baserunners have either heeded that warning or paid the price. And even now, with the 38-year-old Molina’s career possibly winding down, players who were in grade school when Molina debuted with the Cardinals are learning the lesson.

So it was for Astros non-roster invitee Jose Siri in last Sunday’s Grapefruit League contest in Jupiter, Fla. Siri had the audacity to give Molina a finger wag after a close pickoff play; Molina dared Siri to steal, threw him out easily at second and stared him down.

• Hey Siri, show us why you never tempt Yadi

It’s this sort of edge that has helped make Molina a nine-time National League Gold Glove Award winner, two-time World Series champion and quite possibly a future Hall of Famer. The tools are there, obviously, but so is the competitive drive and pride in his work.

“He more than does his part to deter guys from looking to run,” Cardinals manager Mike Shildt said recently. “And when they do, he does what he’s done his whole career -- he’ll cut them down.”

The Siri play sums up Molina’s greatness succinctly. But if you want to understand the depth of his defensive impact throughout his career, consider this stat.

You read that right. Going back to 2004, when a 21-year-old Molina made his MLB debut in June and went on to play in 51 regular-season games, the Cardinals have allowed 847 stolen bases. The next-stingiest team, the D-backs, have allowed 1,250.

That is a difference of 403 stolen bases. To put that in context, it’s greater than the gap (401 steals) between the second-ranked D-backs and 25th-ranked Angels. The Cardinals are in a different universe here.

(The story is much the same if you look not only at successful steals, but all attempts, something the Cardinals blog Viva El Birdos broke down recently.)

So we know that St. Louis -- with Molina the primary catcher -- is head and shoulders above any other team in that time. But what about over the course of baseball history? Surely some other club, at some point, has exhibited similar control of opponents’ running games.

Or maybe not. MLB.com data gurus Tom Tango and Jason Bernard dug into this question, with a big assist from the fine folks at Baseball-Reference. They looked at the difference in stolen bases allowed between the No. 1 and No. 2 teams over every 17-season span since 1916 and found that not only are Molina’s Cardinals first -- they’re nearly twice as far from the pack as anyone else.

Largest SB-prevention gaps between top two MLB teams
Over any 17-season stretch since 1916
1) 2004-20 Cardinals: 403 SB better than No. 2 team
2) 1990-2006 Rangers: 205 SB
3) 1918-34 Senators: 201 SB
4) 1973-89 Yankees: 174 SB
5) 1957-73 Yankees: 164 SB

Note that the list above excludes overlapping spans, as well as expansion teams that did not participate in all 17 seasons. (Since the last two Yankees teams on the list only overlapped by a single year, we’ll make an exception on the first point.) Without that stipulation, the top eight spans all would be from Molina’s time with the Cardinals, extending back to 1997-2013, which encompasses only about half of his career.

Rocket-armed Hall of Famer Iván Rodríguez is one of only two catchers with more Gold Gloves than Molina, along with Hall of Famer Johnny Bench. Pudge, whose first stint with Texas ran from his 1991 debut through 2002, is primarily responsible for the second entry on the list above. Yet even those Rangers teams have been lapped by Molina’s Cardinals. (Other primary catchers for those top-five teams: Muddy Ruel for the Senators, and Thurman Munson and Elston Howard for the Yankees).

It’s not all about the catchers, of course. Pitchers also are instrumental in preventing steals, based on how well they hold runners, how effective their pickoff moves are and how quick they are to the plate. If a pitcher is too slow, a catcher has no chance, no matter how good he is. So give the St. Louis pitching staff credit there, as well as for the fact that since 2004, the team has allowed the third-fewest baserunners in MLB (not counting errors) -- which could also be attributed in some part to Molina’s game calling and receiving. You can’t steal second if you don’t reach first.

Then again, don’t shortchange Molina in this equation. Over the years, he no doubt has dissuaded many runners from trying their luck, based on a reputation reinforced with bullseye throws like the one that nabbed Jose Siri.

Lowest SB success rate allowed, since 2004
1) Cardinals: 64.4%
2) Tigers: 68.4%
3) Reds: 68.9%
4) D-backs: 69.0%
5) Royals: 69.4%
MLB average: 72.4%

During that time, Molina has started at catcher in close to three-quarters of St. Louis’ games, and opponents have succeeded in only 59.7% of their attempts with him behind the plate, although that rate has climbed in recent years. When Molina has not been stationed at home over the past 17 seasons, Cards opponents have stolen at a 73.4% clip -- better than average.

“Yadi is a real deterrent, for sure, and the pitchers are doing their part to give him a chance,” Shildt said. “You do that, and people know that he’s going to be given a chance and the likelihood of them running is not very high. And when they do, their success rate is not really high. He’s a budding Hall of Famer for a reason, and his defense is a part of that, for sure.”

Molina is set to turn 39 years old on July 13, which just so happens to be the date of the All-Star Game, an event to which he’s been invited nine times. After re-signing with St. Louis on a one-year deal last month -- finally ending a prolonged free agency -- he probably will need to rebound offensively to have a shot at selection No. 10.

Regardless of what he does at the plate, however, Molina remains a presence behind it. For 17 seasons, he has controlled the basepaths with an iron grip. The Cardinals have reaped the rewards.