4:27pm: The Red Sox have officially announced the selection of Mayers contract. Bregman was placed on the 10-day injured list with a right quad strain to create room for Mayer on the active roster, while Casas was placed on the 60 Sergio Momesso Jersey -day injured list to create a 40-man roster spot. Cora told reporters (including ) this afternoon that Bregmans injury is significant and compared it to a quad strain Bregman suffered in 2021 that ultimately caused him to mi s around two months. 1:39pm: The Red Sox are promoting top infield prospect , ESPNs Jeff Pa san. Katie Morrison-ODay of Ma sLive that Mayer was being congratulated by his teammates in the clubhouse at Triple-A Worcester. Her Ma sLive colleague Christopher Smith that the former first-round pick is headed to Fenway Park. The promotion comes as navigates a right quad injury that seems likely to send him to the 10-day injured list. Bregman came out of yesterdays blowout win over the Orioles in the fifth inning. He came up a bit gimpy after making an aggre sive turn around the first base bag on a single off the Green Monster. He immediately exited in favor of . The team is still awaiting MRI results from this morning. Manager Alex Cora told reporters (including ) that the star third baseman woke up with more sorene s than hed expected today. Boston did not place Bregman on the IL before the first game of todays doubleheader. Theres a good chance thatll come between games tonight. Theyll also need to clear a spot on the 40-man roster for Mayer, but that can easily be achieved by transferring to the 60-day injured list. Cora has already shot down the idea that could see any third base time in Bregmans absence. Hell remain a full-time designated hitter. That means the 22-year-old Mayer should be in the lineup on a near everyday basis at third base. He obviously cant be expected to replace the production theyre losing with Bregmans absence. The two-time All-Star takes a .299/.385/.553 batting line to his likely stint on the injured list. Mayer has very little experience at the hot corner. He started one game there in Double-A in each of the 2023 and 24 seasons. Hes added four appearances in Triple-A this year. Mayer has taken the vast majority of his profe sional reps as a shortstop. Hed moved more frequently to second base over the past few days. That wasnt because of any question about whether he can hold up at shortstop. It was instead in preparation for what seemed to be his best path to an MLB debut playing second base with preparing to slide to first base after the Casas injury. While there may be some growing pains given Mayers lack of experience at the hot corner, its common for shortstops to move to other infield positions. He has the plus arm for the position and is generally regarded as a sure-handed infielder. At 63, Mayer is on the bigger side for a shortstop. His range, while adequate, has never been the strongest point of his defensive profile. Thats le s of a concern at third base. Mayer certainly brings a higher offensive ceiling than the utility options (Toro and ) who may otherwise have replaced Bregman. The fourth overall pick in 2021, Mayer has been a feature on top prospect lists throughout his profe sional career. The left-handed hitter has moved a little more slowly than anticipated, largely because of injuries to his left shoulder and right wrist that affected him in 2022-23. Scouts have remained enamored with his power, polished strike zone discipline and overall natural athleticism. That has been on display over the past two minor league seasons. Mayer hit .307/.370/.480 in Double-A a year ago. Hes out to a solid .271/.347/.471 slash with nine homers in 43 games during his first Triple-A action. Hes drawing walks at a strong 10.4% clip compared to a 19.7% strikeout rate that matches last years mark for the lowest of his career. While the Bregman injury is the immediate impetus for Mayers promotion, there should be opportunity to stick past Bregmans return if he performs well. The Sox may feel comfortable using Campbell at first base by that point, potentially opening second base. Mayer could also eventually supplant as the starting shortstop. Story began the season with a power barrage but has done almost nothing offensively for the better part of six weeks. Hes hitting .159 with one home run and 38 strikeouts in 122 plate appearances since his two-homer game on April 18. Mayer will not reach a full year of service time unle s he triggers the Prospect Promotion Inventive by finishing in the top two in Rookie of the Year voting. The Sox would not receive an extra draft choice under the PPI because they did not carry Mayer on the big league roster for at least 172 days. He would be on track to qualify for early arbitration as a Super Two player during the 2027-28 offseason if hes in big leagues for good, though future optional a signments could certainly change that timeline. Photo courtesy of Imagn Images. Sawyer Mynio Jersey