Eric Hosmer finally was going to return to Kauffman Stadium this season later this month when the San Diego Padres began a three-game series against the Kansas City Royals.

But that timeline was moved up with a trade-deadline deal that sent Hosmer to the Boston Red Sox, who open a four-game series in Kansas City on Thursday.

The Royals will send Kris Bubic (2-6, 5.45 ERA) to the mound against Boston, which will start Nick Pivetta (8-8, 4.47).

Hosmer didn't appear in Wednesday's 6-1 loss for Boston against Houston. The Royals also lost Wednesday, 4-1 to the White Sox.

Hosmer, the third overall pick of the 2008 draft, was part of the Royals between 2011 and 2017, after which he signed an eight-year, $144 million free agent contract with San Diego. He helped Kansas City reach the World Series against the San Francisco Giants in 2014 and win it in five games against the New York Mets in 2015.

His dash home with the tying run from third on a ground ball with one out in the top of the ninth inning against the New York Mets in Game 5 is an iconic moment in Royals history.

Hosmer hit .284 with an OPS of .781 in 1,048 games over seven seasons with the Royals. In his four 1/2 years with the Padres, he hit .265 with an OPS of .737 in 596 games. Thursday will be his first game against his former club.

Hosmer has been lauded by former teammates -- both with the Royals and the Padres -- for his leadership in the clubhouse as well as play on the field. Now the Red Sox hope he does the same for them in their push to get into the playoffs as a wild card.

"We have struggled to find stability at the first base position this year and we think Eric will provide that," Boston chief baseball officer Chaim Bloom said after the trade. "I think he's going to be helpful between the lines and in the clubhouse and we're excited to get him here. I think he's going to really enjoy our environment. I think he's going to love Fenway Park and hopefully he can help us make a push."

The Royals are in full rebuild mode. They have another young core of position players, including four rookies who have made their major-league debuts in 2022. If they develop like Hosmer did with fellow former Royals Mike Moustakas, Lorenzo Cain and Alcides Escobar, along with current franchise anchor Salvador Perez, the Royals have a chance to contend in the not-too-distant future. But the key will be starting pitching.

Bubic has looked better as of late. In his last three starts (all quality starts), he's allowed five runs in 20 innings. He's struck out 14 and walked just five.

"Probably the things that stand out most to me are just the two mistake pitches that led to some big swings for them and the two four-pitch walks," Bubic said of his night against the Yankees in his last start. "Those can't happen. Other than that, we did a good job rallying back in the fifth to go ahead. I just wanted to keep us in the game."

Bubic is 1-1 with a 9.45 ERA in two appearances (one start) against Boston.

Pivetta is 0-1 with an 8.68 ERA in two career starts against the Royals. He's been streaky, with winning streaks of five and three games, and losing streaks of four and three games. He's lost his last three decisions, with his last victory coming on June 24.