On March 16, 2013, Wilson was optioned to the Triple-A Pawtucket Red Sox to begin the season. He was called up to the Red Sox on April 7 when John Lackey went on the disabled list, and made his Major League debut on April 11. He was optioned to Pawtucket on May 29, and recalled on June 13 when Alfredo Aceves was optioned to Pawtucket. Wilson pitched in the Major Leagues for parts of the 2013 and 2014 seasons. He threw innings for the Red Sox in 2013 and posted a 4.88 ERA. He performed much better in his Major League innings in 2014, recording a 1.91 ERA.
Detroit Tigers
On December 11, 2014, the Red Sox traded Wilson along with Gabe Speier and Yoenis Céspedes to the Detroit Tigers for Rick Porcello. On May 27, 2015, Alex Wilson made his first career major league start for the Detroit Tigers, against the Oakland Athletics, throwing 52 pitches in 3 scoreless innings. Detroit went on to win 3–2. On July 30, 2015, Wilson earned his first major league save, getting the final five outs in a 9–8 Tigers win over the Baltimore Orioles. For the season, he pitched 70 innings, with 16 games finished, 2 saves, a 2.19 ERA and a 1.03 WHIP. During the 2016 season, Wilson set career highs with 62 appearances and 73 innings, while posting a 4–0 record with a 2.96 ERA, with 49 strikeouts and 21 walks. On January 13, 2017, the Tigers avoided arbitration with Wilson, agreeing on a one-year, $1.175 million contract. On August 25, Wilson was ejected for the first time in his Major League career after hitting Todd Frazier with a pitch. This followed after Miguel Cabrera and Austin Romine were ejected for triggering a bench-clearing brawl and after Dellin Betances was also ejected for the first time in his Major League career after hitting James McCann with a pitch. The next day, August 25, Wilson was suspended for four games. He appealed, and had the suspension reduced to three games, which he sat out beginning on September 2. On September 23, 2017, Wilson sustained a non-displaced fractured right fibula after he was hit by a line drive off the bat of Joe Mauer, ending his season. During the 2017 season, Wilson posted a 2–5 record, 4.35 ERA, and 42 strikeouts in 60 innings pitched. On January 17, 2018, the Tigers avoided arbitration with Wilson, agreeing on a one-year, $1.925 million contract. In a game on May 7, 2018, Wilson hurt his foot covering first base, and was later diagnosed with a plantar fascia strain. He was placed on the 10-day disabled list the next day. He returned to action for the Tigers on June 7. For the 2018 season, Wilson pitched innings, posting a 3.36 ERA and 43 strikeouts. On November 30, 2018, the Tigers non-tendered Wilson and he elected free agency.
Milwaukee Brewers
Wilson signed a minor league contract with the Cleveland Indians on February 9, 2019. The deal included an invitation to the Indians' major league spring training camp. He opted out of his contract with the Indians on March 21, 2019 after being informed he would not make the opening day major league roster. Wilson signed with the Milwaukee Brewers on March 24. He was designated for assignment on April 29, 2019 and outrighted on May 1. He was released by the organization on August 3, 2019.
Chicago Cubs
On August 5, 2019, Wilson signed a minor league deal with the Chicago Cubs. He became a free agent following the 2019 season.
Return to Detroit
On January 4, 2020, Wilson signed a minor-league contract with the Detroit Tigers with an invitation to spring training. On June 25, 2020, the Tigers released Wilson. Wilson announced his retirement from professional baseball on July 28, 2020, and joined the Ballengee Group as an advisor.
Pitch selection
Wilson throws three primary pitches. He has a four-seam fastball that averages 92 mph, a two-seam fastball at 88-92 mph, and a slider in the 86-89 mph range. The two-seam fastball is used as both a cutter and a sinker. He throws the cutter more than any other pitch. Wilson also throws an occasional curveball and changeup.
Personal life
Wilson played high school baseball at Hurricane High School where he won a state championship in 2002. Wilson is the second Saudi-born player in MLB history, after Craig Stansberry. Wilson is married to Kristin Wilson.