When Yadier Molina became the full-time starting catcher for the St. Louis Cardinals in 2005, the organization initially lined him up with somewhat typical backup catchers. They weren’t stars, by any means, but backup catchers rarely are. So the likes of Einar Diaz, Gary Bennett, and Jason LaRue were brought around to back up Molina, who, while  relatively durable, was still a catcher and thus needed more off-days than, say, an everyday outfielder.

Following the Cardinals’ one year of deploying Gerald Laird as the backup catcher, one with a starter-backup relationship which was occasionally frought with tension, the Cardinals went with internal option Tony Cruz as Molina’s backup. Cruz was, by any objective measure, not very good in his four seasons as the primary Yadier Molina backup, posting a 54 OPS+ in 561 plate appearances (for perspective, of the 457 individual seasons in Cardinals history in which a player accumulated 561 or more plate appearances, only the 1893 of St. Louis Browns second baseman Joe Quinn was worse at the plate than Cruz’s four years), but he was mostly an afterthought. When Yadier Molina went down with a long-ish term injury in 2014, the Cardinals immediately signed free agent A.J. Pierzynski so as to avoid subjecting themselves to extended bouts of Tony Cruz starting. But on a day-to-day basis, Molina was the most durable catcher in baseball, so spending top-dollar on a quality backup catcher wasn’t the most efficient use of resources.

While the Cardinals attempted to sign a veteran catcher in Brayan Pena, that experiment didn’t work out as planned, and the team reverted to bargain-bin shopping. Eric Fryer had multiple stints as the Cardinals’ backup, and while the team had developed one of the top catching prospects in baseball in Carson Kelly, the Cardinals decided during Spring Training of 2018 that their backup catcher would be veteran Francisco Pena, rather than Kelly, who would start the season in Memphis.

Most assumed that Pena to St. Louis and Kelly to Memphis was more a matter of Carson Kelly’s long-term development than a reflection on who the superior catcher was. Yadier Molina, a superior catcher to Kelly or Pena, takes fewer days off than any other catcher in professional baseball, and MLB teams tend to err on the side of caution when it comes to using their backup catchers in any context other than playing catcher (thus Kelly’s roots as a third baseman, even if he could hit enough to justify occasional starts there, probably weren’t going to be a relevant factor).

If Molina was hurt, and the Cardinals viewed Kelly as the superior talent to Pena, it was very simple–Molina goes to the DL, Kelly gets promoted, and Kelly becomes the regular starter. In the end, Francisco Pena would play in fewer than twenty games all season, and the gap between Kelly and Pena for those games wasn’t so enormous that it was worth stymying Carson Kelly’s development by now allowing him to play regularly.

But when Yadier Molina was sidelined in May with, um, let’s just leave it as “an injury” and not go into further detail, Francisco Pena started 17 games while Molina was on the DL while Carson Kelly started eight. There was more of a timeshare with Pena and Kelly than there had been with Molina and Pena, but Pena was still the overwhelming choice to start. In the time that Yadier Molina was on the DL, Pena had a batting average/on-base percentage/slugging percentage of .238/.279/.365.

Carson Kelly was sent back to the minors when Yadier Molina returned–one could argue that this mix of player development and service time manipulation was not the right move (I wouldn’t, but I get it) but the stance of the Cardinals was certainly consistent. But when Kelly returned to the Cardinals this September, the usage of the backup catchers, particularly when Yadier Molina missed games with an injury, suggested that the Cardinals truly would rather have Francisco Pena behind the plate than Carson Kelly. Pena started on Friday and Saturday, and was the first choice to replace Molina on Wednesday, when Molina was injured.

I wish there were a more delicate way to phrase this, because it seems so unnecessarily cruel to note, but Francisco Pena has never shown signs of being an MLB-caliber catcher, even as a backup. Following his second consecutive start at catcher last Saturday, Pena’s wRC+ (where 100 is considered a league-average hitter, though in fairness, the threshold of acceptability for any catcher, much less a backup one, is much lower) stood at 30. His career mark stood at 45. Among players with at least 129 plate appearances, Pena ranked ahead of only Trayce Thompson and Jesus Sucre in wRC+. Only twelve catchers with as many plate appearances this decade have had worse wRC+ marks for a season. And only one of those twelve players was worse than Pena by Defensive Runs Above Average. Defensive metrics for catchers are infamously unreliable, so forgiving his shortcomings by the numbers would be more sensible if Pena passed the eye test. He hasn’t.

Before this season, Pena played primarily in the minors, and 2017 was his first season since 2010 (where he split time between rookie ball and high-A) in which Pena was an above-average hitter, with a 109 wRC+ in AAA. This season, Kelly had a wRC+ of 107 in AAA, and it was his worst offensive season in three years. And Carson Kelly has long been more acclaimed for his glove than his bat.

Admittedly, Carson Kelly hasn’t been much of a hitter at the Major League level, but it also amounts to fewer plate appearances spread out over three seasons than Francisco Pena has had this season alone. By FanGraphs Wins Above Replacement, the two have been essentially a wash on MLB production, with Kelly having the stronger production in the minors.

That Kelly hasn’t earned the trust of the Major League coaching staff, and that Kelly hasn’t had major breakthroughs in the minors, do give me concern about his big-league future. But this, in September 2018, isn’t about whether Carson Kelly is the future of the Cardinals. It is about whether he is better than Francisco Pena. And he probably is.

I’m no prospect expert, particularly with non-Cardinals prospects, so I consulted a year-old Baseball Prospectus article about the biggest prospect busts in history (there are many more articles about draft busts, but Kelly is a much more highly regarded prospect than he is some highly-drafted amateur). So let’s take a look at the listed catchers.

  • #48: Jeremy Brown
  • #11: Danny Goodwin
  • #2: Jesus Montero

Montero is the most obvious, most recent “enormous catcher bust” comp. But even with his wildly disappointing career, he managed a wRC+ of 92 for his career. His single-season worst wRC+ was 65. Goodwin, a two-time number-one overall pick, was similarly lackluster but managed an 84 wRC+. Even Brown, who barely played in MLB, was above-average in his limited playing time.

In his first start in over three months, Kelly managed two hits. Pena hasn’t had a multi-hit game since May 29. Kelly got the start on Monday night, but it remains to be seen whether he has won over the Cardinals to become the team’s backup catcher or whether Mike Shildt is simply playing the hot hand.

At this point, it is entirely possible and perhaps likely that Pena is only the fourth-best catcher in the Cardinals organization, behind Molina, Kelly, and Andrew Knizner. Unless Francisco Pena is secretly a great pitching whisperer, somebody capable of intangible value that Carson Kelly is not, there isn’t much of an argument for continuing to give him regular starts.