Yet brawn is only part of the reason why Leach is the league's highest-paid fullback playing right now. For the Coke Machine, a nickname that comes from his compact shape, his journey has always been about believing.
Leach never doubted his ability when he was an undrafted rookie out of East Carolina in 2004. He never thought his football career was over when he was cut twice in two weeks in 2006.
Every time he got on the field, he shoved around defenders to open holes, making teams take notice of a position that often is forgotten. By the time he hit the free-agent market this year, there were five teams lined up to sign him.
Leach had gone from just another NFL body to the league's best bodyguard.
"I knew I could always play in this league," Leach said after signing his three-year, $11 million contract with the Ravens. "I knew I always belonged."
Leach's job is a simple one. The 6-foot, 255-pound fullback formerly of the Houston Texans crushes into a linebacker or slams a defensive back on his back.
But that's not his sole purpose on the team. He takes it upon himself to provide the team with leadership and laughs.
According to the Houston Chronicle, he showed up at practice on Halloween Day last year in a Spider-Man costume. And when Texans tight end Owen Daniels began a Pro Bowl campaign by making "Vote for OD" T-shirts two years ago, Leach walked around with a homemade one that read: "Vote for me."
"You can't be a mean man all the time," Leach said. "You have to smile. I am a laid-back guy. On the football field, I turn into a different animal."
Leach can't practice with the Ravens until the players' union recertifies on Thursday. That didn't stop him from making himself at home.
At his first practice, Leach had his arms around guys and was even coaching them.
"You would have thought he has been here for a month," offensive coordinator Cam Cameron said.
This isn't the first time the Ravens players met Leach. It was just last year that Leach led the way for Arian Foster to gain 100 yards against them.
That marked only the third time the Ravens had given up 100 yards to a running back that season. And Leach certainly made an impression.
"I have only played against him one time, but I truly have been a fan of his for years," linebacker Ray Lewis said. "He plays the game the way it should be played, old school, hard-nosed and with passion. I am excited to have him on our side."
Leach's presence and personality are expected to invigorate a sagging Ravens rushing attack. After ranking in the top-5 in 2008 and 2009, the Ravens finished 14th in running the ball last season.
Six days into free agency, the Ravens made Leach the first free agent they signed from another team.
How excited are the Ravens? When reporters asked Ray Rice about the acquisition of Leach, the running back started dancing while singing "I'm So Excited."
"It's always kind of nice if you can get the best," running backs coach Wilbert Montgomery said. "And then if you can keep them to that standard and get him to play at that level again, then you got yourself something."
Montgomery added, "When you bring a guy into the fold like that, the teams in your division, they pay attention to it."
Even if teams don't pay attention to it, Leach wouldn't mind. He has grown accustomed to the anonymity of the position.
Unlike his Ravens' predecessor Le'Ron McClain, Leach isn't counting carries. His seven-year career has produced three carries.
What Leach counts are the number of yards his blocks spring for running backs.
"It feels good to know you play an important position in the offense that not the naked eye really sees," he said. "But your teammates and your peers respect you for what you go out and do and [that you] lay your life on the line every week."
The Ravens, though, have been following a statistic for Leach.
"He happened to have more pancake blocks — and what I mean by pancake blocks [is] he'll put more linebackers on their back — than anybody I've seen in the last four years," Montgomery said. "So, that makes him a powerful stud at his position. And when [I] say a powerful, stud, that's what he does — he looks to pancake guys."
It seemed like early in his career that Leach was the one taking the hits.
In 2004, he wasn't taken in a draft in which 255 players were selected. He joined Green Bay and played three years for the Packers before they released him to make room for receiver Koren Robinson. Leach was then picked up by New Orleans only to get cut two weeks later.
He eventually established himself in Houston and went to his first Pro Bowl last year after paving the way for Foster's league-leading 1,616 yards and 16 touchdowns. When he reached free agency, the Ravens, Houston Texans, Dallas Cowboys, Denver Broncos and New York Giants were fighting for him.
"It makes you feel good to know where I started from," Leach said. "I still can improve and I have a whole lot of work to do. I'm just happy to put myself in a position that somebody wanted me."