I don’t really have baseball card “mail days,” but today I received a card that is part of a group of cards that would set the table for some of the thrilling collection chases in years to come.

I thank my friend Mark for arranging for my newest card for my collection: a 1972 Topps card of Denny McLain, who is best known for his 31-win season in 1968 as a Detroit Tiger that hasn’t been reached by any pitcher since. Actually, McLain has two cards in the 1972 set, but with different teams.

The first 1972 Topps McLain is one I already have: It’s of him as a Texas Ranger, but all of the Rangers cards are unique in that they all pretty much have the same pose. They were the Senators in 1971, and after they moved to Texas for the next season, all of the Rangers cards were printed with the pose of one’s face with the bottom of the cap blocking the cap’s logo. McLain’s card is like that, as well as the rookie cards of Toby Harrah and Jeff Burroughs among others.

The other 1972 Topps McLain card (pictured above) was part of an innovation from Topps that would last for many years, and become an influence for 1980s “XRC” cards such as Roger Clemens, Kirby Puckett and Dwight Gooden. This was the first year of “traded” cards, ones that featured players playing on new teams at the start of the 1972 season. The “traded” concept took about a decade before it became real successful.

As many vintage collectors know, baseball cards were released by series up until 1973. By the time the last series was released, the baseball season was already halfway over and collectors weren’t all that interested in the later series sets. This is why late series cards were tougher to find all on their lonesome, and this making a complete set worth even more money. Final series cards were no different than first series cards, as it had the same mix of individual, rookie and team cards.

By 1971, it must have felt like, what was the point of making the final cards if they were not going to be sold? So for 1972, Topps found a reason to make later series cards worth clamoring for. Actually, two reasons.

One idea was to include “award winner” cards for players who won something during the 1971 season. These were just pictures of trophies, with the names of the winners printed in the essay on the back. It didn’t turn out to be a popular thing.

The other idea was to have “traded” cards (Nos. 751-757) of players who switched teams over the 1971-72 offseason. Topps narrowed their choices down to seven players, of which McLain was a part: Hall of fame players Steve Carlton, Joe Morgan and Frank Robinson; and Jim Fregosi, Rick Wise and Jose Cardenal. These became the original seven “traded” cards. By the time the last series of 1972 came out, these seven players were on cards with their “current” team.

Except McLain.

Baseball cards took a longer while to design and print in those days. The 1972 Topps checklist became committed at a certain time, and by that time the traded cards were included in it. McLain’s history with the Athletics was a very brief one. He only lasted 5 starts and was traded to the Braves on June 29, 1972 for future Hall of Famer Orlando Cepeda. When the McLain traded card came out, he actually was an Atlanta Braves player.

The weirdness of the 1972 Topps McLain cards is doubly intriguing – McLain actually never played for the Texas Rangers, making the earlier card in the set one of the more notable vintage cards featuring a player who never played for the team he’s featured on. McLain was traded from the then-Senators to the Athletics immediately after the 1971 season.

Of the original seven “traded” cards, the McLain is the strangest of the bunch. Robinson’s may be the most sought-out, as it’s the only Robinson card as a Los Angeles Dodger. It should be noted that Robinson’s 1973 Topps card features a photo of him in a Dodgers uniform, but the logo is airbrushed with him written as a California Angel.

The original seven “Traded” cards gave rise to the first parallel traded set from Topps in 1974, which features Hall of Famers Juan Marichal and Ron Santo. Marichal was featured as a Boston Red Sox player, but made just one start before joining the Dodgers (of all teams!) to finish his career. Santo’s card is the first as a White Sox player (of all teams!) After the flop of a “mini” parallel set for 1975, Topps went back to a traded set for 1976, which featured players such as Fergie Jenkins, Mickey Lolich, Willie Randolph, and Oscar Gamble’s big afro. It wasn’t until 1981 when traded sets became a major player in the newly competitive nature of the baseball card market, rivaling Donruss and Fleer.

The traded sets of the 1980s, as mentioned, gave rise to the issue of “XRCs,” “extended rookie cards” issued for a year’s set release before their actual “RC” rookie card release. Most notable are the 1984 Fleer Update cards of Clemens and Puckett, which were only available via factory set. Many traded sets were only sold in set form until the 1990s. If you wanted a Clemens card in 1984, instead of waiting for the 1985 sets to come out, you had to buy the boxed set of the 1984 design in which it came in.

Featuring the seven “traded” players in 1972 gave rise to a collecting phenomenon that followed in the next decade. Traded and Update sets would give collectors a chance to collect a card of a player who otherwise wouldn’t have been featured on that team in a regular base set. I recently purchased a complete set of 1985 Topps Traded, and it featured Al Oliver as a Dodger, Don Sutton as an Athletic and George Hendrick as a Pirate. Those guys wouldn’t be featured on those teams in any base set since they swapped teams mid-season.

I’m glad I now own McLain’s only Athletics card. It completes my McLain team arc (1969 Tigers, 1971 Senators, 1972 “Rangers,” 1972 Athletics and 1973 Braves).