Cardinals manager Oliver Marmol said Friday that O'Brien will be shut down for a few days due to a mild right calf strain, Brian Murphy of MLB.com reports.

EDGE Analysis

It will take a couple weeks for O'Brien to ramp things back up, so it will be at least the beginning of March before he's ready to pitch in spring training games. O'Brien is also now unlikely to pitch for Team South Korea in the World Baseball Classic, though he will remain in the player pool in case there's a chance he can be added later. The injury could also affect O'Brien's chances at opening the season as the Cardinals' closer. He is in the mix for saves with JoJo Romero and perhaps Matt Svanson.

O'Brien is managing calf soreness that is being evaluated Tuesday, Jeff Jones of the Belleville News-Democrat reports.

EDGE Analysis

It's unclear exactly how O'Brien sustained the injury, but it puts his availability in question for Team South Korea for the upcoming World Baseball Classic. After recording six saves and six holds with a 2.06 ERA, 1.15 WHIP and 45:22 K:BB over 48 innings last year, the 31-year-old righty is expected to be in the mix for saves to begin the year for St. Louis.

O'Brien struck out the only batter he faced to earn the save in Tuesday's 9-8 win over the Giants.

EDGE Analysis

JoJo Romero faced the minimum three batters in the ninth inning, leaving with two outs and Matt Chapman on second base after a double. O'Brien came in and struck out pinch hitter Wilmer Flores on five pitches to strand the tying runner. This was O'Brien's sixth save of the year, all of which have come since Ryan Helsley was traded to the Mets. For the season, O'Brien has added six holds while maintaining a 1.96 ERA, 1.11 WHIP and 43:21 K:BB through 46 innings.

O'Brien picked up the save in Tuesday's 3-0 win against the Reds, striking out one in a perfect ninth inning.

EDGE Analysis

With JoJo Romero once again handling the eighth, O'Brien was entrusted with a three-run lead in the ninth and made quick work of the heart of Cincinnati's order, needing just nine pitches to lock down his fifth save of the year. It marked the right-hander's third save in his last five appearances. The 30-year-old now sports a 2.08 ERA, 1.15 WHIP and 41:20 K:BB across 43.1 innings this season.

O'Brien picked up the save in Sunday's 3-1 win at Milwaukee, allowing one walk and no hits over a scoreless inning with two strikeouts.

EDGE Analysis

The 30-year-old worked around a two-out walk to collect his second save of the month. O'Brien, who fired 10 of his 16 total pitches for strikes, got the ninth after JoJo Romero pitched a scoreless frame in the eighth against the heart of the Brewers lineup. Although Romero is likely to draw the majority of save opportunities, St. Louis manager Oliver Marmol has shown no hesitation in employing O'Brien when the situation arises. The righty reliever now sports a 2.13 ERA, 1.17 WHIP and 40:20 K:BB in 42.1 total innings.

O'Brien was charged with three runs and pulled from a save chance without recording an out in Saturday's loss to the Brewers.

EDGE Analysis

The Cardinals turned to O'Brien with a three-run lead in the bottom of the ninth inning, and he allowed four straight batters to reach -- the first two via hit-by-pitch -- before being lifted. Kyle Leahy then came on and allowed one of two inherited runners to score, adding another run to O'Brien's ledger. The three earned runs charged to O'Brien match the number he had allowed over his previous 29 appearances combined. He should remain in the mix for saves for St. Louis down the stretch.

O'Brien earned the save in Sunday's 4-3 win over the Giants, allowing one hit in a scoreless ninth.

EDGE Analysis

With JoJo Romero being deployed in the eighth inning, the Cardinals turned to O'Brien -- who was credited with the win Saturday -- to close things out in the ninth. O'Brien gave up a single to open the inning, but he got out of the inning unscathed after getting Patrick Bailey to ground out into a double play. O'Brien has not yielded a run in nine of his last 10 outings and sports a 1.60 ERA and 1.09 WHIP across 39.1 innings this season.

O'Brien (3-0) struck out one in a scoreless frame and was credited with a win in Saturday's victory over the Giants.

EDGE Analysis

O'Brien missed more than a week of action with right shoulder discomfort, but he showed no ill effects Saturday, displaying his normal velocity and needing only eight pitches to retire the Giants in order in the top of the ninth. The reliever picked up his third win of the season after the Cardinals rallied for three runs to walk it off in the bottom of the frame. As long as he stays healthy, O'Brien will remain in the late-inning mix for St. Louis.

The Cardinals are hopeful O'Brien (shoulder) will be available to pitch Friday against the Giants, the St. Louis Post-Dispatch reports.

EDGE Analysis

O'Brien hasn't pitched in a week due to lingering right shoulder soreness, but he played catch earlier this week and could be cleared for game action after the team's off day Thursday. The 30-year-old collected two saves and three holds in August and boasts a 1.69 ERA and 35:17 K:BB over 37.1 innings this season.

O'Brien (shoulder) was cleared to play catch Monday and could avoid the 15-day injured list, Daniel Guerrero of the St. Louis Post-Dispatch reports.

EDGE Analysis

O'Brien underwent an MRI on Monday due to lingering right shoulder discomfort, but the Cardinals were encouraged by the imaging results and the reliever was allowed to resume throwing. While a stint on the IL has not been ruled out, O'Brien will be given a couple days to continue to recover to see if a long-term absence can be avoided. The 30-year-old has emerged as a late-inning bullpen arm for St. Louis this season, collecting a 1.69 ERA and 35:17 K:BB over 37.1 innings while notching two saves.