Julio Daniel Martinez (born August 21, 1987) is an American professional baseball outfielder and designated hitter who is a free agent.

He has played in Major League Baseball (MLB) for the Houston Astros, Detroit Tigers, Arizona Diamondbacks, Boston Red Sox, Los Angeles Dodgers, and New York Mets.

Martinez played college baseball at Nova Southeastern University (NSU) and was selected by the Astros in the 20th round of the 2009 MLB draft.

He is a six-time MLB All-Star selection and a three-time Silver Slugger Award winner, as well as the only player to earn the latter honor twice in the same season.

On September 4, 2017, Martinez became the 18th player in MLB history to hit four home runs in a single game, doing so versus the Los Angeles Dodgers.

[4] Martinez started the 2011 season with Corpus Christi; over 88 games, he batted .338/.414/.552/.959, 25 doubles, 13 home runs, 72 RBIs, 42 bases on balls, and 55 strikeouts.

With a runner on in the eighth, he hit an Edward Mujica offering into the Clevelander bar beyond the left-field wall for a game-tying home run.

The next month, while in the trainer's room after spraining his left wrist, Martinez watched ESPN highlights of Milwaukee Brewers' slugger Ryan Braun batting.

The day after the season ended, Martinez was in Santa Clarita for an appointment[9] with hitting experts Robert Van Scoyoc and Craig Wallenbrock.

[10] After two weeks in Santa Clarita, Martinez traveled to play for the Leones del Caracas in the Venezuelan Professional Baseball League.

[15] Martinez was named the Detroit Tigers' Player of the Month for June, posting a .345 average with nine doubles, seven home runs and 21 RBIs, including a career-high 14 game hit streak.

[16] Martinez authored a breakout regular season in 2014, finishing with 30 doubles, 23 home runs, 76 RBIs, .315 batting average, and a .912 OPS,[17] all career-highs to that point in his major league career.

[20] Martinez finished the postseason with one double, two home runs, and five RBIs in three games as the Tigers were swept by the Orioles.

[21] On June 21, Martinez hit three home runs and had six RBIs in a game against the New York Yankees, becoming the first Tigers player to do so since Miguel Cabrera did it in May 2013.

[24] Martinez finished the season with a .282 batting average and reached career highs of 33 doubles, 38 home runs, and 102 RBIs.

[25] His 38 home runs marked the third-highest total by a Tigers outfielder, trailing only Rocky Colavito's 45 in 1961 and Hank Greenberg's 41 in 1940.

[30] Martinez was placed on the 15-day disabled list after a June 16 game against the Kansas City Royals, having suffered a non-displaced fracture in his right elbow caused by running into the outfield wall.

[31] On August 3 against the Chicago White Sox, in his first game after being activated from the disabled list, Martinez hit a pinch-hit game-winning solo home run off Chris Sale on the first pitch of the at-bat.

[36] On July 18, 2017, the Tigers traded Martinez to the Arizona Diamondbacks for Dawel Lugo, Sergio Alcántara, and Jose King.

Martinez won the following National League (NL) Player of the Week Award—ending September 10—after batting .429, seven total home runs, and 11 RBIs.

[39] On September 17, Martinez recorded his 40th home run of the season, doing so against the San Francisco Giants, and reaching the milestone for the first time in his career.

His combined achievements with Detroit and Arizona in 2017 included a .303 batting average in 119 games played and new career-highs in each of 45 home runs, 104 RBIs, .376 OBP, and eight intentional walks.

[48] On April 7, Martinez hit his first home run in a Red Sox uniform at Fenway Park, doing so off Chaz Roe of the Tampa Bay Rays.

The previous record of 24 had been achieved by Ted Williams (1950), Mo Vaughn (1996), Jose Canseco (1996) and Manny Ramirez (2001).

[51] Batting .329 with 27 home runs and 73 RBIs,[52] Martinez was named to the 2018 MLB All-Star Game as the American League's starting designated hitter.

[53] Spanning one full season of play from the 2017 MLB All-Star Game to July 14, 2018, he led the major leagues in home runs (60), RBIs (152), and OPS (1.074).

[66] When asked about exercising his opt-out clause following the club's final regular season game, Martinez responded, "I don't mind moving around.

He became the fifth player in history to hit three home runs in one game for three different teams after Johnny Mize, Dave Kingman, Alex Rodriguez, and Mark Teixeira.

[80] On November 7, Martinez declined his opt-out clause for the third straight year, choosing to remain with the Red Sox for the 2022 season.

[91] On June 13, in a game against the Miami Marlins, Martinez hit his first career walk-off home run, off of pitcher Tanner Scott.