Joseph Anthony "Trey" Mancini III[1] (born March 18, 1992) is an American professional baseball first baseman, outfielder, and designated hitter in the Arizona Diamondbacks organization.

He has previously played in Major League Baseball (MLB) for the Baltimore Orioles, Houston Astros, and Chicago Cubs.

After spending some time in Baltimore during spring training,[13] Mancini returned to Bowie to start the 2016 season.

[18] On September 20, in his major league debut as the designated hitter against the Boston Red Sox, he hit a home run against Eduardo Rodríguez in his second at bat.

[19] Mancini started again two nights later and hit his second career home run, a three-run homer off David Price.

He became the third player in major league history to homer in their first three starts, after he hit a solo home run against the Arizona Diamondbacks on September 24.

[citation needed] On June 7, in a game against the Pirates, Mancini hit a game-tying, pinch-hit two-run home run in the ninth inning off closer Tony Watson.

Two innings later, with two on and two outs, Mancini hit a walk-off three-run home run off Wade LeBlanc to give the Orioles a 9–6 victory.

Mancini finished the season batting .293/.338/.488 with a .826 OPS, 120 OPS+, 24 home runs and 78 RBI in 147 games during his rookie campaign.

[22] He set a career high with five hits in an 11–4 win over the Toronto Blue Jays at Rogers Centre on September 24, 2019.

On June 28, 2020, Mancini was placed on the 60-day injured list and missed the entire 2020 season due to recovery from Stage 3 colon cancer surgery.

[28] Mancini returned to the Orioles at the beginning of spring training and appeared in the team's first game of the preseason, against the Pittsburgh Pirates.

[31] On July 28, 2022, Mancini hit an inside-the-park home run with a runner on base that started as what appeared to be a routine sacrifice fly.

However, the ball deflected off the cheek of Tampa Bay right fielder Josh Lowe after he lost it in the afternoon sun and hit him in the face, allowing Mancini to score.

[34] On August 5, Mancini hit his first career grand slam against Hunter Gaddis of the Cleveland Guardians as part of a two-homer, 5 RBI day.

He would end up making a game-saving play, snagging a hard-hit ball by Kyle Schwarber to get the Astros out of a jam and preserve their 3–2 lead.

[51] Mancini first met Sara Perlman in 2017, when she worked for MASN, covering the Baltimore Orioles and Washington Nationals.

The couple began dating after Perlman left MASN for NBC Sports, as host of The Daily Line.