Casas (rib) underwent an MRI on Monday that confirmed the expectation that he'll be out for a significant length of time, Julian McWilliams of The Boston Globe reports.

The Red Sox haven't placed a timetable on Casas' return, but it seems likely he'll blow past the 10-day minimum on the injured list. For now, the team plans to get by with a combination of Bobby Dalbec, Pablo Reyes and possibly Rob Refsnyder, who has been working at the position since the start of spring training. Another option is for Boston to wait and see what happens after May 1, when several players could exercise opt-out clauses.

Mountcastle isn't in the lineup for Monday's game against the Angels due to knee soreness, Steve Melewski of MASNSports.com reports.

Skipper Brandon Hyde noted the team is holding Mountcastle out of the lineup in the series opener simply as a precaution. Hyde also stated that the first baseman will be available off the bench Monday if the situation arises.

Manager Kevin Cash said Aranda (finger) is expected to begin a rehab assignment with Triple-A Durham later this week, Steve Carney of StPeteNine.com reports.

Aranda had the pins removed from his surgically repaired right ring finger a week ago, and he looks to be nearing a return to game action. The 25-year-old has been sidelined for the past month, so he'll need a good number of rehab at-bats before being activated from the 10-day injured list. Aranda had been in line to serve as the Rays' primary designated hitter against right-handed pitching before getting hurt.

Naylor went 2-for-4 with a two-run home run and an additional RBI in Saturday's 6-3 win over the Athletics.

Naylor has hit safely in eight straight games, going 11-for-33 (.333) with three homers and eight RBI in that span. The first baseman is thriving in the cleanup spot, slashing .329/.400/.630 with six homers, 17 RBI, 13 runs scored and four doubles over 85 plate appearances, but he's also been caught stealing on both of his attempts this year. Naylor has trimmed his strikeouts rate to 11.8 percent and upped his walk rate to 9.9 percent. He's never hit more than 20 homers in a season, but he's also never exceeded 122 contests, so an everyday role seems to be in part helping his increased production.

France went 2-for-5 with a run in a win over the Rockies on Saturday, marking his sixth and seventh times on base within his last 10 plate appearances.

The hot stretch encompasses the last three games for France and began with a pinch-hit appearance in which he drew a walk against the Reds on Tuesday. The veteran infielder is sitting on an impressive .288 average and .348 on-base percentage, while his slugging percentage checks in at a much more modest .339 since he only has a trio of extra-base hits (all doubles) over 66 plate appearances. However, France is demonstrating improved discipline at the plate -- his 9.1 percent walk rate is a career high, while his 27.7 percent chase rate is significantly lower than the 37.8 percent figure he finished 2023 with.

Noda went 2-for-4 with a double and a solo home run in a loss to the Guardians on Saturday.

Noda authored the only multi-hit effort of the game for the Athletics, accomplishing the feat for the first time all season in the process. Noda's leadoff round tripper in the fifth inning was also his first time clearing the fences in 2024, and although his slash line still sits at a forgettable .190/.288/.293 through 67 plate appearances, he's now hit safely in three straight contests.

The Red Sox placed Casas on the 10-day injured list Sunday with a left rib strain, Mac Cerullo of the Boston Herald reports.

The 24-year-old exited Saturday's contest with rib discomfort and will now be sidelined for at least the rest of April after being diagnosed with a strain. According to Chris Cotillo of The Springfield Republican, manager Alex Cora responded "yes" when asked if he was concerned about a lengthy absence, but there should be more clarity on the situation after Casas visits with a specialist Sunday. Bobby Dalbec is the only other player with a start at first base this season and should have an expanded role while Casas is sidelined. Tyler Heineman was recalled from Triple-A Worcester in a corresponding move.

Vaughn is not in Sunday's starting lineup against the Phillies.

Over his last 10 appearances, Vaughn has slashed .135/.238/.216 with three doubles and one RBI while registering a 38.1 percent strikeout rate. Gavin Sheets will start at first base and bat in the cleanup spot against Phillies right-hander Aaron Nola.

Lowe went 0-for-3 with a walk and run scored in Saturday's 5-2 loss to Atlanta.

Lowe was activated off the injured list and made his season debut, batting fifth and playing first base. He should be the primary first baseman going forward against lefties or righties.

Red Sox manager Alex Cora said Saturday that Casas is undergoing tests for a rib injury, Chris Cotillo of The Springfield Republican reports.

Cora noted that it's not an oblique injury which forced Casas from Saturday's game against the Pirates after just one plate appearance. However, the skipper admitted to having some concern about the first baseman, so it certainly seems as though the injury list is a possibility. The results of Casas' tests should be available later Saturday or Sunday.