Den Dekker returned to Florida in 2019 to resume his schooling, while also becoming a student assistant coach for the Gators. In 2020, den Dekker was named the hitting and outfielding coach for the Charleston Southern Buccaneers.
When Chapman signed on to play college baseball for the Florida Gators, den Dekker quickly followed suit.[4] As a freshman, he batted .234/.324/.418. As a sophomore, den Dekker hit .333/.413/.507 with 20 steals in 20 tries and 55 runs in 55 games. The center fielder was a first-team All-Southeastern Conference selection as an outfielder. Den Dekker was then chosen for Team USA's college edition. He batted .176/.375/.176 in the 2008 Haarlem Baseball Week; noted for his defense, he made one error and noted for his speed, he was thrown out in his lone attempt (gunned down by Cuban defensive legend Ariel Pestano in the gold medal game). Den Dekker batted .227/.292/.409 in the 2008 World University Baseball Championship, and did not attempt a steal.
Den Dekker hit .296/.409/.412 as a junior with 17 steals in 18 tries. He was still rated 92nd overall by Baseball America among prospects entering the 2009 Major League Baseball draft – then was not selected until the 475th overall pick, when the Pittsburgh Pirates selected him in the 16th round. He returned to Florida for his senior year, hitting .358 with a team-leading 64 runs scored and a career-best 49 runs batted in as the Gators reached the 2010 College World Series.
In 2013, den Dekker received his third invitation to the Mets Spring training camp. He played in a career-high 19 games and posted a .205 batting average as he went 9-for-44 with one home run and seven runs batted in while striking out 16 times. On March 24, den Dekker broke his right wrist attempting to make a play on a fly ball hit by Detroit Tigers outfielder Austin Jackson.
On August 27, the Mets promoted den Dekker to the major leagues.[7] He made his major league debut on August 29.[8] He hit his first MLB home run on September 1, off Ross Ohlendorf of the Washington Nationals.[9] For the season, he batted .207/.270/.276.[10]
Washington Nationals
On March 30, 2015, the Mets traded den Dekker to the Washington Nationals for pitcher Jerry Blevins.[11]
Den Dekker was optioned to the Syracuse Chiefs at the end of Spring Training on April 1, 2016. He was recalled on April 6 when Ben Revere was placed on the disabled list.[12] After the Nationals optioned him back to Syracuse later in the season, den Dekker hit just .208 before being taken off the 40-man roster and outrighted to the minors on September 3.[13] For the season, he batted .176/.282/.294.[10] He elected free agency following the season on November 7.[14]
Miami Marlins
On November 30, 2016, den Dekker signed a minor league contract with the Miami Marlins organization.[15] On May 2, 2017, he opted out of his contract, becoming a free agent.[16]
Detroit Tigers
On May 16, 2017, den Dekker signed a minor league deal with the Detroit Tigers.[17] He was called up by the Tigers on June 23.[18] On July 5, 2017, he was designated for assignment and sent outright to the Toledo Mud Hens four days later.[19] For the season, he batted 1-for-7.[10] After the 2017 season, den Dekker elected free agency.
Return to the New York Mets
On February 15, 2018, den Dekker returned to the New York Mets, signing a minor league contract with an invitation to Spring Training. Den Dekker had his contract selected on July 11, 2018. He was designated for assignment on July 27, 2018.[20] On October 2, 2018, he elected to become a free agent.[21]
Long Island Ducks
On March 26, 2019, den Dekker signed with the Long Island Ducks of the independent Atlantic League of Professional Baseball.[22] On June 7, he announced his retirement from professional baseball.[23] In 29 games he hit .268/.336/.446 with 2 home runs, 12 RBIs and 4 stolen bases.