Leon, who spent the first few weeks of the 2019 season in Triple-A, was behind the plate, batting eighth when the Red Sox took on the rival Yankees in New York on Tuesday night with Chris Sale on the mound. He went 0-for-3 with two strikeouts as Boston lost the series opener, 8-0.
Leon spent much of 2018 as Sale's personal catcher, and many on the Red Sox pitching staff speak glowingly of his ability to call a game. In 2018, he led the majors with a 3.29 catcher's ERA in 89 games.
Sale pitched better Tuesday night but still ended up taking the loss, allowing four runs in five innings, striking out six and walking one.
"We know what his strengths are. Handling the pitching staff is one of them. He brings a lot of intangibles to the club the way he handles the staff," president of baseball operations Dave Dombrowski said before Tuesday's game.
"It's a decision we decided to make at this point. I'm not saying it's the sole reason we've struggled, but it'll help us. When you have a club that's struggling a lot in different areas, and we are, which a lot of times clubs do. You try to fix little things at a time."
When asked if the Red Sox underestimated Leon's value to the pitching staff, Dombrowski disagreed.
"I don't think we underestimated it. By no means are we putting this on Blake because our guys haven't pitched very well," Dombrowski said. "It was a combination of factors. We felt like it was a good time to bring up a veteran-type catcher to handle a veteran pitching staff. That's what we're excited for."
Christian Vazquez has been the team's primary starting catcher. Manager Alex Cora said that the team expects the playing time to be split similarly to 2018, when Vazquez played in 80 games and Leon caught in 89.
Leon says he worked on simplifying his swing while in Triple-A.
"Just trying to get back to my simple swing and not strike out that much," Leon said. "I know I can't hit 30 homers, but I gotta do a better job than I did last year."
Cora told Leon before the game that he doesn't need the catcher to be Superman and solve everyone's problems.
"I told Sandy, don't feel like you have to come up here and be the savior. It doesn't work that way," Cora said. "There's a comfort level. We know what he's done the last few years. Nothing against Blake, obviously. You know how we feel about him, too. It's one of those baseball decisions."
Swihart, once the top prospect in the Red Sox farm system and a 2011 first-round pick, has struggled with injuries since making his major league debut in 2015.
Drafted as a catcher, Swihart first hit the injured list in 2016 after spraining his left ankle during a collision with the wall along the left field foul line while playing outfield at Fenway Park. Swihart also spent significant time in 2018 on the IL, nursing a strained hamstring.
Swihart spent the first two months of the 2018 season as the 25th man on the Red Sox, without minor league options.
In an effort to create more playing time, Swihart added the infield and outfield to his defensive arsenal but received 30 at-bats in the first 50 games of the season. The 27-year-old finished the year hitting .229/.285/.328 with three homers and 18 RBIs in 82 games.
In 203 games with the Red Sox, Swihart hit .255/.314/.365 with nine homers and 58 RBIs, accumulating 0.3 WAR.