O'Neill (hamstring) was sent to Triple-A Memphis to begin a rehab assignment Saturday, Jenifer Langosch of MLB.com reports.

EDGE Analysis

O'Neill has been out since July 5 with a left hamstring strain. Given the timing, he'll likely spend a few days in Memphis before returning to St. Louis after the All-Star break, though he's not a lock to return to the majors once healthy.

O'Neill was placed on the 10-day disabled list Thursday with a left hamstring strain.

EDGE Analysis

It's unclear as to when O'Neill suffered the injury, but he'll likely remain out until after the All-Star break. He was promoted from Triple-A Memphis on July 1 and went 1-for-6 in three games prior to hitting the disabled list.

The Cardinals recalled O'Neill from Triple-A Memphis on Monday.

EDGE Analysis

O'Neill may only be in store for a short-term stay in the majors after assuming the roster spot of Dexter Fowler, who will be on the paternity list for the next three days. The power-hitting outfielder has smacked 22 home runs this season -- including three with the Cardinals -- but making consistent contact has been an issue. He struck out in 18 of his 41 plate appearances (43.9 percent) across his previous two stints in the big leagues.

O'Neill will be called up to the big leagues prior to Monday's game against the Diamondbacks, Jenifer Langosch of MLB.com reports.

EDGE Analysis

O'Neill will be called up to replace Dexter Fowler, who's expected to miss the Cardinals' upcoming series with Arizona while on paternity leave. In 16 games with St. Louis this season, O'Neill is batting .237 with three home runs and seven RBI

O'Neill, who'd been without a home run for eight consecutive games since returning to Triple-A Memphis on May 31, went 2-for-5 with a pair of solo homers and three RBI overall in a win over Albuquerque on Wednesday.

EDGE Analysis

The prodigious slugger's long-ball drought was exceedingly rare, considering he'd blasted a jaw-dropping 13 round trippers in his 29 prior games with the Redbirds. O'Neill hadn't been struggling during that stretch despite not leaving the park, however, as he'd hit safely in five straight contests at one point. Wednesday's breakout effort pushed his Triple-A line to .317/.363/.676, starkly different numbers from the .237/.268/.500 he's slashed over 41 big-league plate appearances thus far.

O'Neill was demoted to Triple-A-Memphis on Thursday.

EDGE Analysis

O'Neill will head to the minors after struggling at the dish over his last four games. He went 0-for-11 with eight strikeouts during that span. Through 16 games with the Cardinals, O'Neill hit .237 with three home runs and seven RBI.

O'Neill, who went 0-for-4 with two strikeouts in a loss to the Brewers on Wednesday, is 0-for-11 with eight whiffs over his last four games overall.

EDGE Analysis

The slugging rookie got his latest big-league stint off to a blistering start by slugging three home runs and compiling six RBI overall in his first four games. However, O'Neill is just 2-for-19 overall in the subsequent six games, a stretch that includes the aforementioned 0-for-11 slump. Contact continues to be a monumental challenge for O'Neill, whose 43.9 percent strikeout rate is playing a significant part in his recent struggles.

O'Neill homered and knocked in four in a 2-for-4 game Monday against Kansas City.

EDGE Analysis

O'Neill won't even let the Cardinals think about taking his bat out of the lineup. The 22-year-old is now an absurd 7-for-12 with homers in all three games he has started since coming back to the majors May 18. O'Neill, a third round pick in 2013, has been one of the most enticing power prospects in the minors and is showing why in his second crack at the show after going 0-for-7 in six games in a stint this April. At this rate, he'll prove he not only belongs in St. Louis, but in the Cardinals outfield on a daily basis.

O'Neill hit the first home run of his big league career -- a solo shot -- in Saturday's loss to the Phillies. He finished the day 1-for-3 with a walk in addition to his homer.

EDGE Analysis

O'Neill's first stint in the bigs resulted in seven hitless at-bats, but he seems to have figured things out after being sent back down to the minors. He collected his first big league hit Friday and followed it up with his first longball Saturday off of Luis Garcia. O'Neill has intriguing power but St. Louis' stacked outfield consisting of Tommy Pham, Marcell Ozuna, and Dexter Fowler will make it tough for him to carve out a regular role.

O'Neill entered Friday's win against the Phillies in the seventh inning as a defensive replacement and went 1-for-1 with a run.

EDGE Analysis

The 22-year-old had just been recalled from Triple-A Memphis, where he's been tearing the cover off the ball with 13 home runs over 113 at-bats. O'Neill had gone hitless in nine plate appearances in his one prior Cardinals stint this season, so Friday's seventh-inning single marked the first major-league hit.