The deal is worth $11.5 million over two years and contains a $6.25 million vesting option for 2016.
Ken Gurnick of MLB.com has the details.
Howell would be guaranteed $11.25 million, with a $6.25 million salary in 2016 if he makes 120 appearances the first two seasons.
The team would not confirm the agreement, which is believed to be contingent on the passing of a physical exam.
Howell was a durable and reliable complement to fellow left-hander Paco Rodriguez in 2013 after signing late in the offseason when the Dodgers realized that Scott Elbert wouldn’t be healthy in time.
Howell, a left-handed pitcher, was 4-1 with a 2.03 ERA in 2013. He allowed 14 earned runs on 42 hits and 23 walks and struck out 54 batters in 67 appearances. He pitched 62.0 innings. In the postseason, Howell pitched 6.0 innings in seven appearances. He gave one earned run, a home run on five hits and three walks while striking out six.