LAKE BUENA VISTA, Fla. -- Mike Matheny can't help but keep track. Few former catchers can. When one of his backstops gets down and makes a big block, he notes it. When a pitch isn't received correctly, he notes that, too. Matheny is hard-wired to catalogue the little things, and in this category, catcher Francisco Pena continues to impress.
The 28-year-old Pena built on his strong spring back there Saturday, when he traveled with the club to Disney's Wide World of Sports complex and caught six innings of St. Louis' 3-0 blanking of the Braves. Luke Weaver and five relievers combined to allow just one hit, mostly with Pena on the receiving end.
Signed as a depth option over the winter, Pena figured to catch most days at Triple-A Memphis until Cards No. 9 prospect Andrew Knizner arrived, with No. 3 prospect Carson Kelly backing up Yadier Molina at the big league level. But Pena now holds the inside track to the job as Molina's understudy, after the club optioned Kelly to Memphis on Sunday. Kelly slumped on both sides of the ball this spring, prompting Cardinals officials to pivot from their original plan. The risk of Kelly sitting through "a lost year" playing sporadicaly behind Molina, as Cardinals president of baseball operations John Mozeliak described it, threatened his development.
Even at age 34, Molina led National League catchers with 133 games played behind the dish last year.
Kelly is ranked as the No. 2 catching prospect in all of baseball.
"He's still young enough, we're still excited enough about his future, that it makes more sense for him to be playing every day and growing as a player, than simply trying to watch and learn but not actually experience," Mozeliak said.
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Whether its Pena or Steven Baron who wins the backjob job, neither would unseat Kelly in the Cardinals' long-term plans. But both would provide short-term insurance to an essential, if little-used position. Were anything to happen to Molina, Kelly would be summoned. 
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Pena is the son of former longtime MLB catcher Tony Pena. He profiles as a prototypical backup catcher, and has been used primarily as defense-first organization depth for more than a decade, with the Mets, Royals and Orioles. He is not fleet of foot and has struggled to hit consistently over 11 Minor League seasons. But he brings a strong arm, good receiving skills and fundamentals in spades. The club tracked several of Pena's throws to second this spring in the 1.80-second range, which is considered an elite pop time.

Injury update
Luke Gregerson traveled with the club but wasn't scheduled to pitch a day after throwing a 27-pitch live bullpen session to test his strained right oblique. He reported no issues and is expected to pitch Sunday against the Nationals. Gregerson has been limited to one appearance this spring.
Something green
The Cardinals were one of several teams across Major League Baseball to wear festive green accessories in celebration of St. Patrick's Day. St. Louis wore all-green hats, while Paul DeJong and a few brave others donned lime-colored socks.
Old friends reunite
Three of the last four half-innings Saturday were handled by veterans and former teammates who had considerable impact on past Cardinals teams.
Lefty Sam Freeman, who spent his first three seasons in St. Louis, worked a scoreless top of the eighth for Atlanta. Jason Motte, back with the Cardinals on a Minor League deal this spring, pitched a scoreless bottom of the frame.
Then the Cardinals called on former All-Star closer Edward Mujica to finish the game. Mujica, who saved 37 games for the 2013 Cardinals team that reached the World Series, was a late-spring borrow from Minor League camp.
"Blast from the past," Matheny said.

Up next
St. Louis will continue to stretch out righty John Gant in the event it needs rotation depth come summer. Gant has been piggybacking behind other starters this spring, and Sunday he gets his first start, when the Cardinals return home to take on the Nationals at 12:05 p.m. CT, live on MLB.TV.