The outbreak of COVID-19 that crept through their clubhouse and kept the Cardinals quarantined for nearly a week in a downtown Milwaukee hotel left the team and Major League Baseball retracing steps to determine where and when the virus found a way in.

It also prompted an online search party for blame and vague reports that caught the attention of a Milwaukee casino.

Based on the tweet of a former major-league player and the headlines it spurred, Potawatomi Hotel & Casino reviewed who visited their casino on Thursday and forward and determined they had no record of a visit from a member of the Cardinals, a spokesman for the casino told the Post-Dispatch on Wednesday afternoon. Due to health and safety protocols, a reservation and membership is required to enter the casino in addition to other measures. That allowed the casino to review their patrons and they found no evidence of a visit by a member of the Cardinals.

This was important for the casino to do because the Cardinals were in Milwaukee all day Thursday before learning of two positive tests, and the spokesman agreed that their search was a public health measure.

The team has vehemently denied that they have any evidence of the players breaking from protocols while on the road trip. Major League Baseball has concurred with this view, according to two sources outside of the Cardinals organization.

"I have no factual reason to believe that is true and I have not seen any proof of that," said John Mozeliak, president of baseball operations, when asked directly by the Post-Dispatch about the casino report. "If they were at a casino though, that would be disappointing."

Cardinals manager Mike Shildt said Wednesday that the team has traced the genesis of the outbreak back to an outside individual who was asymptomatic when he had contact with a member of the club. "Brought it into our clubhouse," Shildt said. From there, the virus spread through practices that the Cardinals have also internally addressed. 

The nature of the tweet from Jerry Hairston Jr., a former big-leaguer and now a broadcast analyst, did not offer where or when the Cardinals were alleged to have gone to a casino, and that allowed for a wide range of speculation and confusion — on the public's part and the team's.

"Hearin (sic) a few Cardinals went to a Casino?" the tweet read.

The question mark further muddies the allegation.

A subsequent tweet from a report that confirmed the report also did not specify where the visit to the casino took place, and it could have been one of several players advertised on social media — but did not actually involve going into a casino.

On July 12, outfielders Harrison Bader and Dexter Fowler posted photos on Instagram of them attending a Nelly concert in St. Louis with former outfielder Jim Edmonds. The venue was Hollywood Casino Amphitheater — a name that has been repeated as the casino Cardinals were said to have visited. It's not a casino, though. The concert was drive-in and outdoors, and the players shared photos of them wearing masks or enjoying the concert at a distance from atop the car.

In his post, Fowler called himself a "Social Distance Genius" for sitting atop his car.

The concert was also more than 18 days before the outbreak.

Such photos however drew added scrutiny as a result of the team's 13 positive tests. Fowler and infielder Kolten Wong shared images on social media from their round of golf Thursday at Whistling Straits in Sheboygan County, Wisconsin, though a team official said players were allowed and even encouraged to get outside while practicing safe habits. Mozeliak added later that players were not "locked in their rooms" — until they were because of the spike in positive tests.

Other photos, including one of two pitchers visiting an Illinois lake, were also unearthed to show Cardinals in the wild without masks. An alleged photo of a Cardinals player at an unidentified casino before the team left for Minneapolis was determined not to be of a Cardinal at all, two sources with knowledge of the inquiry described.

The vagueness of the report does not specify if it was a misunderstanding of the concert, an implication of a visit in Milwaukee that the casino said isn't possible, or some stop in St. Louis or Minneapolis. Attempts today to trace any root of the casino report to those cities have been unsuccessful.

The team has refuted any break from protocols in the Twin Cities after the team arrived.

The first two positive tests came as a result of tests taken Wednesday night in Minneapolis. That gives the Cardinals and Major League Baseball some sense of where the initial contact with the virus was made because players are tested so regularly they can see when there is a switch from negative to positive.  

The Cardinals believe the first exposure happened before the team left from St. Louis and that the spread began possibly on the team charter to the Twin Cities and accelerated during the series against the Twins.

"Clearly something happened that allowed this to get into our space," Shildt said. "I take exception with the reports — and I can't say that everybody was ultra-responsible at every, single, waking turn. But I can tell you this is a responsible group. My understanding on how it got in is from an outside source, not anybody in our group going out and doing anything. I think reports to that are pretty irresponsible, quite honestly. The fact of the matter is somebody got it, asymptomatic, brought it into the clubhouse.

"Listen, as far as the protocols go we'll continue to be diligent."