"I feel like I've had a pretty good camp this summer," Marshall said. "I think I've improved a lot of things and shown coach that I can play as a freshman.
"I've just been working on getting the plays down and knowing the assignments so it's second nature. That way I can just get in there and perform to the best of my ability, I won't have to think too much about what I have to do or what my assignments are."
Even though he has seen some reps with the first-team this fall, Marshall, who prepped at Valley Christian High School in San Jose, still admits that getting those reps has been tough.
"There are so many talented backs on this squad," Marshall explained, "and I feel humbled just to get in there and get reps with the ones, it's a good experience."
Marshall was listed by Scout.com as the No. 5 running back in the state of California among the 2009 class, and was named the Offensive Player of the Year on the All-Northern California Team. He also earned All-County and All-Bay Area recognition as he rushed for 1,904 yards and 24 touchdowns as a senior.
Still only 17 years old, Marshall is one of the youngest players on the team, but where this may intimidate most; Marshall has embraced his situation and tries to learn as much as he can.
"It's interesting, but I feel I'm able to learn a lot from the older guys so it's good to be one of the younger players," Marshall acknowledged. "You've got a lot of people up they're supporting you and helping you out."
Whatever he is learning from the older guys appears to be working for the running back, who is making the jump from high school to college look easy even though he states otherwise.
"In high school senior year, once you're the top dog, it gets easy at times, but here it's challenging every single play," Marshall commented. "There really isn't much room for error up here as there was in high school."
Even with his preseason success, the freshman remains levelheaded and focused on what he wants to accomplish this season.
"I'm trying to get a lot of carries, some big runs, and a lot of touchdowns, just have a really outstanding year," Marshall noted. "Right now I'm looking forward to Idaho State and just going out there, playing hard and doing my best."
One of his fellow freshmen who has seen some success this fall as well is five-star linebacker recruit Vontaze Burfict, who's hit on Marshall in Wednesday's practice was all over the news.
"Ha, yeah he got me pretty good yesterday," Marshall mentioned. "We were talking trash and stuff and he told me he was going to get me, and he got me, but I told him I was going to get him back, so we'll just have to wait and see."
Burfict isn't the only talented player on the Sun Devil defense, and Marshall confesses that going against that unit every practice is tough.
"We're playing against a great defense every day," Marshall said, "and we struggle a lot, but on the days we don't struggle it just gives us even more confidence as an offense. It's tough though."
This offense could use the assurance too. Most don't expect much out of this side of the ball for the Sun Devils this year, but Marshall feels that it only makes the group better.
"That motivates us a lot," Marshall noted. "We read the stuff too saying that the offense isn't expected to do much or that the running backs aren't expected to do much, but we just take that as motivation to do better."