The person spoke Friday night on condition of anonymity because the trade did not get completed.
Marmol's contract gives him the right to submit a list of up to five teams he can't be traded to without his consent. The person said Marmol told the Cubs he would consent to the trade, but would not say whether the reliever provided his written consent.
The deal was first reported by the Chicago Sun-Times. A spokesman for the Cubs declined to comment.
The Angels had until midnight EDT on Friday to exercise Haren's $15.5 million option for next season. He had a $3.5 million buyout. The 32-year-old right-hander went 12-13 with a career-worst 4.33 ERA in 30 starts this year and was on the disabled list for the first time.
Haren, a three-time All-Star from 2007-09, would be the second starting pitcher traded by the busy Angels in three days. Los Angeles shipped Ervin Santana to the Kansas City Royals on Wednesday for minor league left-hander Brandon Sisk.
Marmol, an All-Star in 2008, had 114 saves for the Cubs over the past five years. Yet he lost his job as the team's closer several times due to ineffectiveness and a lack of control.
The 30-year-old righty was 3-3 with a 3.42 ERA in 61 appearances this year. He had 20 saves in 23 chances but walked 45 in 55 1-3 innings.
Marmol is set to make $9.8 million next season and then can become a free agent. He had a career-best 38 saves in 2010, when he struck out 138 in 77 2-3 innings and finished an NL-high 70 games.