Hamilton is starting at third base and batting seventh Opening Day against the White Sox on Thursday.

The lefty-hitting Hamilton will end up getting the Opening Day nod at the hot corner over switch-hitting veteran Luis Rengifo, who inked a one-year $3.5 million deal with Milwaukee in February. Hamilton played in 91 regular-season games with Boston last year and finished the campaign with six homers, 22 steals and a .198/.257/.333 slash line in 177 plate appearances.

Lee has won a spot in Atlanta's Opening Day bullpen, Chad Bishop of The Atlanta Journal-Constitution reports.

The 31-year-old figures to be the top left-hander in the bullpen, although he could face competition from Aaron Bummer for that assignment. Lee is coming off a career-best 2025 season in which he recorded 19 holds, more than doubling his previous best, along with a 3.29 ERA, 0.98 WHIP and 76:14 K:BB over 68.1 innings for Atlanta.

Heim has secured a spot on Atlanta's Opening Day roster, Chad Bishop of The Atlanta Journal-Constitution reports.

It will likely be a temporary assignment while Sean Murphy (hip) is on the IL, but Heim will back up Drake Baldwin to begin the season. Heim hasn't been able to match his career-best 2023 campaign with the Rangers, and over the last two seasons the 30-year-old switch hitter managed just a .217/.269/.334 slash line.

Mateo claimed a spot on Atlanta's Opening Day roster, Chad Bishop of The Atlanta Journal-Constitution reports.

The veteran utility player will provide some extra depth at shortstop behind Mauricio Dubon while Ha-Seong Kim (finger) is on the IL. Mateo has stolen double-digit bases in each of the last five seasons despite inconsistent playing time -- he went 15-for-17 on the basepaths in 2025 despite seeing just 83 plate appearances for the Orioles.

House will start at third base and bat third in Thursday's opener versus the Cubs.

The righty-swinging House will likely hit toward the bottom of the batting order against right-handed pitching, but he'll occupy a prime spot in the lineup versus lefty Matthew Boyd. House stung the ball in spring training, slashing .429/.444/.786 with three home runs, though his usual plate-discipline issues (1:11 BB:K) remained.

Kinley will begin the season as part of Atlanta's bullpen, Chad Bishop of The Atlanta Journal-Constitution reports.

No surprise here after Kinley posted a 0.72 ERA, 0.68 WHIP and 22:6 K:BB over 25 innings for Atlanta last season following his trade from the Rockies, and then re-signed with the NL East squad on a one-year, $4.5 million deal this offseason. Raisel Iglesias and Robert Suarez will be the top right-handed high-leverage arms for Atlanta, but Kinley could still post strong a strong holds total as one of the primary options for the seventh inning -- his career high in holds is 15, set in 2024 for Colorado.

Garcia is not in the lineup for Thursday's opener against the Cubs.

With left-hander Matthew Boyd toeing the rubber for the Cubs, the lefty-swinging Garcia will yield to Andres Chaparro at first base and Nasim Nunez at second base. Garcia is a career .237/.260/.331 hitter versus southpaws.

Jackson is out of the lineup for Thursday's game against the Twins.

Though Jackson beat out a number of competitors for the final position-player spot on the Orioles' Opening Day roster, he looks like he'll have to settle for a part-time role to begin the season, even while Jackson Holliday (hand) and Jordan Westburg (elbow) are on the injured list. Coby Mayo is expected to be Westburg's primary replacement at third base, while the Orioles could opt for a more of a timeshare between Jackson and Blaze Alexander at the keystone in Holliday's absence. The Orioles will turn to Alexander at second base for the opener.

O'Neill will start in right field and bat sixth in Thursday's opener versus the Twins.

It's righty Joe Ryan on the bump for the Twins, but the right-handed-hitting O'Neill will nonetheless get the call in right field as he attempts to extend his major-league record Opening Day home run streak to seven. Dylan Beavers has been battling a knee/quad injury recently, which also could have played into Orioles manager Craig Albernaz's decision to start O'Neill. The two players are expected to share the right-field job this season.

Ward will start in left field and bat leadoff in Thursday's opener against the Twins.

Jackson Holliday (hand) is likely to bat leadoff when he returns to action, but it will be Ward at the top of the batting order on Opening Day as the Twins send righty Joe Ryan to the hill. Ward sported a .425 on-base percentage for the Orioles during spring training, logging more walks (eight) than strikeouts (seven).