Strasburg will receive a rolling opt-out clause after the third or fourth year of the contract and could receive $7 million in performance bonuses, sources said. He also will receive an additional $1 million bonus each season he reaches 180 innings pitched, according to sources.
The Nationals plan to make an official announcement Tuesday, The Washington Post reports. Strasburg deflected questions about his contract after Washington's win Monday night, saying, "I don't really have a comment about that right now."
Asked about his comfort level in Washington, Strasburg said, "Growing up in Southern California, San Diego, all my life and stuff, the East Coast is a little bit of a change. But the city of D.C. has been great to me and my family. It's really grown on us. We're very comfortable here."
Strasburg, who avoided arbitration in January when he agreed to a one-year, $10.4 million deal, was set to become a free agent after this season and would have been the premier pitcher available. He is represented by agent Scott Boras, who typically forgoes extensions in favor of having his clients test the open market. Boras told Fox Sports during spring training that discussions about an extension would wait until the end of the season.
Strasburg, 27, a San Diego State product, was drafted first overall by the Nationals in 2009. In six-plus major league seasons, he has a career record of 59-37 with a 3.06 ERA.
He also has made six trips to the disabled list, including in 2010, when he underwent Tommy John surgery to repair a torn ulnar collateral ligament in his right elbow. He rebounded from that procedure to become an All-Star in 2012, when he won 15 games and helped lead the Nationals to their first playoff appearance since moving to Washington in 2005, although the team shut him down before the postseason to protect his elbow. In 2014, Strasburg recorded 242 strikeouts, tied for most in the majors.
This season, Strasburg was 5-0 with a 2.36 ERA in his first six starts, having allowed just one home run in 42 innings.
His seventh start came Monday against the Detroit Tigers. He allowed four earned runs on six hits, including two home runs, and struck out 11 over seven innings in the Nationals' 5-4 win for a no-decision. He was saluted with a standing ovation when he was pulled after walking the leadoff batter in the eighth, presumably because the crowd had heard about his new contract.
"His mental state of mind, his calmness, is a whole lot better, I heard, than it used to be, where some of the small things don't affect him as much," Nationals first-year manager Dusty Baker said. "We had a conversation in the spring about that he's no longer an underclassman. He's been here a while."
David Price's deal with the Boston Red Sox that started this season is worth a record $217 million over seven years. Another of the few deals for a pitcher that tops Strasburg's is the one his Nationals teammate Max Scherzer received as a free agent before last season, paying $210 million, although half of that is deferred money.
ESPN's Buster Olney and The Associated Press contributed to this report.