The Dolphins were last in the league last year in rushing yards, totaling only 1,156. Quarterback Ryan Fitzpatrick led the team with 243 yards.
Howard should immediately step in as the Dolphins starting running back though Miami is still expected to target a RB in the first three rounds of the draft with J.K. Dobbins, Jonathan Taylor, Clyde Edwards-Helaire and Zach Moss drawing strong early interest.
After racking up 3,370 rushing yards over his first three NFL seasons with the Chicago Bears, Howard was traded to the Eagles last offseason and emerged as the team's No. 1 back over rookie Miles Sanders.
Howard, who turned 25 in November, finished out his rookie contract last season with 525 rushing yards and six touchdowns in nine games. But he suffered a shoulder stinger in Week 9 that basically cost him the rest of the season. Howard was active for the final two games, demonstrating that the injury had healed, but he hadn't regained enough strength in the shoulder at the time to have a meaningful role in the offense.
Howard was deemed not to be a fit in coach Matt Nagy's offense with the Bears after his three-year rushing total from 2016 to '18 was the third in the league -- behind only Ezekiel Elliott and Todd Gurley.
A fifth-round pick in 2016, Howard made the Pro Bowl in his rookie season after rushing for 1,313 yards in 252 attempts -- an average of 5.2 yards per carry -- while scoring seven total touchdowns. He followed that up with another 1,122 rushing yards and nine touchdowns in 2017.
Overall, he has 3,895 yards on 897 attempts -- an average of 4.3 yards per carry -- and all but two of his 32 career touchdowns have come on the ground.
The Dolphins are also adding former Eagles linebacker Kamu Gruiger-Hill on a one-year deal, a source confirmed to ESPN.
ESPN's Cameron Wolfe and Tim McManus contributed to this report.