According to Chelsea Janes of the Washington Post, that offer did not include any opt-out clauses.
Ken Rosenthal of The Athletic noted the Nats likely knew Harper wouldn't accept the offer, and he mentioned Washington as a "fallback" for Harper if he doesn't get the deal he wants.
Last year, an anonymous MLB general manager suggested to ESPN.com's Eddie Matz that Harper could land a $400 million contract in free agency.
On Tuesday, Nationals GM Mike Rizzo told ESPN.com that Washington isn't giving up on bringing Harper back into the fold: "We've had conversations and we utilized our exclusivity to negotiate with him late in the season through when he became eligible to sign with a team. We didn't get anything done, but he's a guy that is near and dear to us and we are not closing any doors."
The 26-year-old Harper is coming off his sixth All-Star nod in seven MLB seasons after he hit .249 with 34 home runs and 100 RBI in 2018.
While Harper's batting average left something to be desired, he walked an MLB-leading 130 times and posted an on-base percentage of .393, good for ninth in the majors.
Harper made his MLB debut in 2012, just two years after the Nationals selected him with the No. 1 overall pick in the MLB draft. He was named the National League Rookie of the Year, and three seasons after that, he won the National League MVP Award when he hit .330 with 42 homers and 99 RBI.
In 927 career games, Harper is hitting .279 with 184 home runs and 521 RBI.
Because of his age and impressive resume, Harper is seemingly in line to land a record-breaking contract. His agent, Scott Boras, has the reputation and skills to get him that sort of deal.
Harper leads a strong free-agent class that includes shortstop Manny Machado, starting pitcher Dallas Keuchel, closer Craig Kimbrel and several other top-flight options.