According to The Associated Press, the agreement is subject to a successful physical. MLB Network and ESPN reported that the deal includes a full no-trade clause, no opt-outs and no deferred money. Harper gets a $20 million signing bonus, a $10 million salary this year, $26 million in each of the following nine seasons and $22 million in each of the last three years.
The tentative deal would be the richest contract by total value in baseball history, surpassing the 13-year, $325 million agreement Giancarlo Stanton reached with the Miami Marlins before the 2015 season. News of the Harper signing comes a week after the San Diego Padres signed shortstop Manny Machado to a 10-year contract worth a reported $300 million.
Harper, 26, spent the first seven years of his career with the Washington Nationals, who drafted him with the first overall pick in 2010. Harper made his major league debut in 2012, when he hit 22 home runs and drove in 59 runs en route to winning the National League Rookie of the Year Award.
In 2015, Harper had his best season, batting .330 with a .460 on-base percentage, 42 home runs, 99 RBIs, 118 runs, 124 walks and an OPS of 1.109 as he was voted the National League's Most Valuable Player.
Harper played in 159 of a possible 162 games this past season, batting .249 with a .393 on-base percentage. He hit 34 home runs with 100 RBIs and was an All-Star for the sixth time in his career. He started more than a third of his games in center field instead of his usual spot in right, because of injuries to teammates.
With Washington's Nationals Park hosting the 2018 All-Star Game, Harper stole the show the day before the Midsummer Classic by winning the Home Run Derby before an ecstatic crowd filled with folks wearing his No. 34 Nationals jersey. Harper wore a headband with the D.C. flag's design, reflecting his oft-stated pride in playing for Washington.
Washington D.C. Mayor Muriel Bowser thanked Harper in a Twitter post, but added: "It was a good 7 years, But in 33 days When we play the Phillies, Beating you will be nice."
But that eventually ran its course. The Nationals made an offer toward the end of last season — a $300 million, 10-year contract that was no longer on the table after free agency opened without an agreement.
A year after going 82-80 and missing the playoffs under rookie manager Dave Martinez, the Nationals will move forward without Harper.
Washington general manager Mike Rizzo would have loved to keep Harper in his team's lineup but didn't sit around and wait to find out whether that would happen. Instead, Rizzo spent such money elsewhere, adding lefty starter Patrick Corbin on a $140 million deal and righty starter Anibal Sanchez, along with second baseman Brian Dozier, a pair of catchers in Yan Gomes and Kurt Suzuki and two key bullpen pieces in Trevor Rosenthal and Kyle Barraclough.
Philadelphia has been among the most active teams this offseason, adding outfielder Andrew McCutchen for $50 million over three years and reliever David Robertson for $23 million over two years, and acquiring catcher J.T. Realmuto and shortstop Jean Segura. They also gave ace Aaron Nola a $45 million, four-year deal.
After leading their division in early August, the Phillies went 16-33 over the final 49 games of last season and at 80-82 finished with a losing record for the sixth straight season. Philadelphia has not made the playoffs since 2011.
The Associated Press contributed to this report.