Marcelo Mayer’s long-awaited Triple-A debut, which will officially put him just one degree of separation away from Major League Baseball, is officially on hold.

On Tuesday afternoon, a team source confirmed Alex Speier’s report for the Boston Globe that the Red Sox top prospect is going on the 7-day Triple-A injured list.

The shortstop, 21, is still dealing with lingering soreness in his hip and upper glute areas. He didn’t accompany the team on this week’s road series to play the Orioles’ affiliate Norfolk Tides in Virginia.

It’s been over a week since the Red Sox promoted Mayer (No. 5 on MLB Pipeline’s league-wide prospect rankings), outfielder Roman Anthony (No. 14), and catcher Kyle Teel (No. 27) – the trio labeled Boston’s new Big Three – to Triple-A (August 12). The shortstop had been one of Double-A Portland’s most productive hitters, averaging .307 with a .850 OPS, 92 hits, 28 doubles, eight home runs, and 13 stolen bases in 77 games.

Mayer, however, last played on July 30. His ongoing injury is the same one that landed him on Double-A Portland’s 7-day IL on August 1, and though he was activated in the days leading up to his promotion, he didn’t play during that brief window.

His Triple-A debut, too, has already been pushed back at least twice over the last week. “We’re shooting for Saturday,” he told the Herald last Thursday, after fielding grounders and doing other baseball activities at Polar Park. As of Sunday, he was slated to debut in Tuesday’s series opener with Norfolk.

There is a strategic element to the roster move: the WooSox still consider Mayer ‘day-to-day,’ but officially placing him on the IL opens up a roster spot, rather than playing a man short, as they did throughout the first six-game series after his promotion. However, injuries are becoming a concerning pattern for the organization’s No. 1 prospect. In 2022, right-wrist and back issues limited his first full professional season to 91 games. Last year, a shoulder impingement limited Mayer to 78 games between High-A Salem and Double-A, and ultimately cost him the last six weeks of the MiLB season. Between mid-June and late July this year, he missed games due to left lower-leg soreness, back discomfort, and pectoral soreness.

Now, not only has an injury Double-A initially thought would require no more than the minimum requisite days lingered for most of the month, it’s put his Triple-A debut and remainder of the season in jeopardy. Even if he’s activated as soon as the minimum days are up, he’ll have missed nearly a full month of the minor league season, which wraps up one week before the final Red Sox game on Sept. 29.