That changed in the quarterfinal round of the playoffs last December against St. Cloud State.
The redshirt freshman broke out for a Northwest record four rushing touchdowns in a postseason game, and eclipsed 100 yards for the first time in his career.
"It was a blessing to me," Jackson said. "And from that experienced I feel like I learned a lot, and that helped me with this camp. And it's going to help me moving forward."
Now a year older, that performance propelled Jackson into the driver's seat on the Northwest depth chart.
The Carol Stream, IL native is in line to start the season opener as the number one tailback for the defending national champs.
"It means a lot, it honestly means a lot. It means that the coaches trust me, and I'm not going to lose their trust. I'm going to do everything I can to do everything right."
"Phil earned his way to being the number one back right now," head coach Adam Dorrel said. "Now it's up to him to keep it there."
After bursting on to the scene as a bruising back at 6-feet, 220 pounds, Jackson's added more speed to his game in the offseason.
"This summer I tried to break down my body, tried to get back into that groove of being a running back, you get hit a lot, stuff like that," Jackson said. "I'm going to still try to be that bruiser, along with bringing the speed. So I'm going to try to give a little bit more of a balance."
That balance is important to what the Northwest offense is trying to execute.
"We always talk about, don't be a one trick pony at running back, be able to do other things other than run the football," Dorrel said. "Be good blitz pick up guys and catch the ball out of the backfield, and we're looking for guys that are going to give great second effort."
Jackson's rounded out his game by improving his pass blocking, and this fall, when he gets his touches, it won't come as a surprise to anyone.