For one new Red Sox acquisition, the call that he’d been traded marked a dramatic left turn in his baseball journey. Danny Jansen had spent his entire 11-year professional career with the Toronto Blue Jays, and in an instant he and his family were about to uproot their lives to join a whole new organization.

James Paxton wasn’t expecting to change teams this week either, but when he walked back in to the Red Sox clubhouse Sunday, he saw familiar faces everywhere he looked.

“It feels like I never left,” said Paxton, who spent the past two seasons in Boston before signing with the Los Angeles Dodgers as a free agent last winter.

Paxton and Jansen both arrived in Boston Sunday and are expected to quickly make an impact on a Red Sox team with playoff aspirations. Jansen immediately slotted into the lineup as the designated hitter Sunday night, and Paxton is scheduled to make his first start back with the Red Sox on Tuesday against Seattle.

“Definitely a little bit mixed emotion. Maybe a little caught off guard, a little surprised, but after it all settled I was really excited to be a part of this organization,” Jansen said of being traded. “Very grateful to be here and help in any way I can for this team to make a postseason push.”

For Jansen, the next few days will be a crash course in learning the Red Sox pitching staff. Manager Alex Cora said Jansen has already put in long hours working with catching coach Jason Varitek, pitching coach Andrew Bailey and fellow catcher Connor Wong, and that he’d come highly recommended from people in Toronto, including ex-Red Sox designated hitter Justin Turner.

Jansen said he’s already enjoyed getting to learn from Varitek.

“Incredible, he’s already put me under his wing and brought me in there and helped me out a lot to get the feel for it and get up to speed and talk about each guy,” Jansen said. “Connor was doing the same and helping out trying to get me up to speed. Definitely excited to work with him, talk with him and learn as much as I can.”

As for how Jansen fits into the equation, Cora said his right-handed bat is well suited for Fenway Park and they envision him peppering the Green Monster will pull-side line drives. He will also help balance a roster that’s tilted heavily left-handed all season, and should see a good amount of time as a DH against left-handed pitching.

Cora added that Wong will get the majority of the playing time at catcher, but he also suggested Wong could still see time at other positions on days where Jansen is working behind the plate.

“Connor is going to catch the majority of the games, but I’ll tell you this right now, don’t be surprised if you see Connor start taking more ground balls at second base or first base,” Cora said. “He’s that versatile and he’s such a good athlete.”

Paxton’s addition will allow Cooper Criswell to slide over to the bullpen while giving the Red Sox a left-handed starter to throw at opposing lineups. Though Paxton is familiar with the Red Sox, he hasn’t worked with new pitching coach Bailey and his staff yet, so the hope is to get him up to speed on the new pitching program and help bring down his walk rate, which has ballooned to a career-high 12.3%.

Paxton also confirmed that he was interested in returning to Boston as a free agent this past offseason and that his decision to sign with the Dodgers was “totally a location thing.”

“We wanted to be on the west coast closer to home, my wife wanted to be on the west coast, and happy wife, happy life,” Paxton said. “We decided to stay on the west coast, but I love Boston and I’m really excited to be here the rest of the season.”