Buck Allen's celebration with his little brother on Saturday went beyond getting drafted by the Baltimore Ravens in the fourth round. It was a moment for the USC running back to reflect on a journey filled with challenges, tragedy and heartbreak.

"I know when it all calms down later on, I’m going to sit [by] myself, and I just know I’m going to tear up and cry and think about all the stuff me and my family went through to get to this point," Allen said. "It’s a blessing.”

To reach the NFL, Allen had to overcome grueling hardships while growing up. Raised by his grandmother, Allen lost his father figure at the age of 12 when his older brother went to prison on attempted murder charges. When he reached high school, he went to live with Mickey and Alice Cullen, assistants at the local Boys and Girls Club. Alice passed away from breast cancer in 2009.

To honor her, Allen writes "Alice" in black marker on tape over his left wrist. After he scores a touchdown, he kisses his wrist and points to the sky.

"It’s a whole lot of emotions," Allen said. "When I first started out, I never had a celebration at all. But [it is about] pretty much letting it all out, and you have so much built inside."

The Ravens selected Allen with the No. 125 overall pick after he led USC in rushing the past two seasons and finished third on the team in receptions last season. In 2014, he ran for 1,489 yards and 11 touchdowns and caught 41 passes for 458 yards.

Even though Allen isn't expected to make the same immediate impact as running backs Melvin Gordon or Todd Gurley, who were selected in the first round, he has the potential to develop into an every-down back. He was the only player in the country to record 13 games of at least 100 yards from scrimmage.