Pena was placed on the 15-day DL on Wednesday with left knee inflammation.

EDGE Analysis

The Cardinals will lose some catching depth behind Yadier Molina, but other than that this shouldn't have much of an impact on their lineup. The 34-year-old had appeared in just four games this season, slashing .125/.222/.125 while failing to tally a run or RBI. Alberto Rosario was called up in a corresponding move.

Pena announced on Twitter this Tuesday that he will be joining the U.S. Army Reserve this offseason.

EDGE Analysis

Pena, 34, defected from Cuba years ago and is currently an American citizen. He has apparently been contemplating joining the Army for some time, although his contract prohibits fully enlisting in the Army. While the announcement doesn't affect Pena's ability to play for the Cardinals this season, it looks like his career might not last much longer once the season is up.

Pena (knee) was activated from the disabled list Tuesday, Derrick Goold of the St. Louis Post-Dispatch reports.

EDGE Analysis

Following an extended rehab assignment at the Double-A and Triple-A levels, Pena will replace Eric Fryer as the Cardinals' backup catcher. Pena has yet to play in the majors this season, and he had just 10 hits (all singles) in 52 at-bats during his stay in the minors.

Pena (knee) is expected to be activated off of the disabled list on Tuesday, Jenifer Langosch of MLB.com reports.

EDGE Analysis

In a corresponding move to activate Pena, the Cardinals expect to designate current backup catcher Eric Fryer for assignment. Over Pena's 20-day rehab assignment, he slashed an unimpressive .192/.218/.192.

Pena (knee) rejoined the Cardinals on Monday but will not be activated prior to their game, Jenifer Langosch of MLB.com reports.

EDGE Analysis

This is a good sign as Pena is likely to return very soon. The 33-year-old has yet to play at the major league level in 2016, but he did hit .273/.334/.324 in 108 games with the Reds last season. Once activated, he will likely serve as a reserve to Yadier Molina.

Pena (knee) took a leave from his rehab assignment at Double-A Springfield for personal reasons, Derrick Goold of the St. Louis Post-Dispatch reports.

EDGE Analysis

It's unknown when Pena will return to his rehab assignment, but Cardinals manager Mike Matheny says it should be sometime in the near future. In his time with Springfield, Pena has shown mobility behind the plate, but has just three hits after 19 at-bats. Upon his return, Pena will remain in the minors for additional at-bats so he can fix his timing at the plate.

Pena (knee) will begin his rehab assignment Tuesday at Double-A Springfield.

EDGE Analysis

Pena has been on the shelf since spring training due to some loose cartilage in his left knee that had to be surgically removed. He was initially expected to miss only a month, but the veteran has taken slightly longer than expected to get back behind the plate. Regardless, Tuesday marks a major step forward in his progression towards returning to the Cardinals. Given the length of his absence, St. Louis may opt to keep him on the rehab assignment for several games while he gets re-acclimated to game action.

Pena (left knee surgery) ran at 65 percent effort on the field Wednesday and hit coach-pitched balls in the cage, MLB.com's Jenifer Langosch reports.

EDGE Analysis

It doesn't sound like Pena is all that close to going on a rehab assignment, but it's encouraging that he is making strides in his recovery. Running tests, particularly taking turns on the bases, as well as spending time in his catching crouch will be key hurdles he'll have to clear in the coming weeks.

Pena (knee) will go through several running tests Wednesday as he continues his recovery, the St. Louis Post-Dispatch reports.

EDGE Analysis

Pena has been working on his arm strength for a while now but he'll have to get his legs back to 100 percent before he's activated from the disabled list.

Pena (knee) underwent surgery Tuesday and is expected to need about a month to recover, MLB.com's Jenifer Langosch reports.

EDGE Analysis

The surgery was to remove a loose piece of cartilage from his left knee, and while the club initially believed it might only be a two-week recovery, the team is now prepared to be without him for the rest of April. He should serve as the Cardinals backup catcher when he rejoins the team in May.