"We wanted to work really hard at regaining the mentality about running the football," Carroll said on the John Clayton Show on 710 ESPN Seattle. "That's something that's really important to us. We knew that we lost that edge last year when Russell [Wilson] was hurt and when Thomas [Rawls] was hurt. Both those guys were injured for eight weeks, nine weeks, or something during the season. So it took us a while to get going. And we didn't find the kind of rhythm that we wanted."
The Seahawks finished 23rd in rushing efficiency last year, the first time they had finished below seventh in Wilson's five seasons as their quarterback. Offensively, when the Seahawks have been at their best, they've incorporated three elements. One is a punishing run game. Two is a quick-hitting passing game that makes up for issues in pass protection. And third is a play-action attack that can lead to explosive shots downfield.
Seattle is hoping Lacy can be a factor in the run game even when the blocking isn't perfect. And really, the signing is the latest attempt at what the Seahawks have wanted to do for years: find a replacement for Marshawn Lynch.
Even when Lynch was on the roster, Seattle tried to be proactive. From 2012 to 2016, the Seahawks spent seven draft picks on running backs. In 2013, they drafted Christine Michael in the second round, and the previous year it was Robert Turbin in the fourth.
Last year, the Seahawks used three draft picks on running backs, taking C.J. Prosise in the third, Alex Collins in the fifth and Zac Brooks in the seventh. But despite those investments, the Seahawks still have not been able to find a physical, durable back who can give them what Lynch gave them for so many years.
"We went all those years with Marshawn, and everybody knew what we stood for and the style of play," Carroll said. "So I'm hoping to just continue to add now with Eddie. And the way Thomas brings it, that's a great one-two punch sending a message about playing tough and physical. And that's who we are. And that's who we want to continue to be. So that's why we've made this move."
Stylistically, Lacy is a good fit. Since he entered the NFL in 2013, he has averaged 2.15 yards after contact (sixth-best). As a point of reference, during Lynch's prime (2011 to 2014), he averaged 2.05 yards after contact.
In a small sample size, Lacy looked good last year, carrying 71 times for 360 yards (5.1 YPC). He's shown he can be a workhorse (717 carries in his first three NFL seasons) and is a better receiver than he's been given credit for (101 career receptions for 900 yards).
But in free agency, there is always risk. The team that lets a player go -- in this case, the Green Bay Packers -- has more information on him than the new team does. Lacy has battled weight issues and played only five games last year after suffering a season-ending ankle injury.
Which Lacy are the Seahawks going to get? Will he be able to stay in shape and lead their rushing attack? Or will his weight and conditioning be an issue?
Carroll said he's counting on Lacy to be extra motivated since he's on a one-year deal. And the team still envisions roles for Rawls and Prosise.
But with the commitment the Seahawks are making to Lacy, they clearly believe he will be key in jump-starting their run game in 2017.
"We've really respected his play for years, and even going back to draft time, because of the way he plays the game," Carroll said. "He's really tough, and he's physical, and he's a big load, and he's a big back in classic fashion. So he's an exciting guy to add to the mix. Thomas brings us great energy, and C.J. and Alex both add in too. So I think it can make a really good position group for us. We'll find a good rotation in here to help everybody out. But I like that we're bringing in a big, tough guy that's going to send a message [in] the way he plays the game."