David Johnson

For the last two weeks, Arizona Cardinals rookie running back David Johnson has been trying to find the right balance between returning to the field and making sure his hamstring injury doesn't linger.

It wasn't easy for the third-round pick, who coach Bruce Arians said will return to practice Monday.

"You can feel good but you don't know until you start running," Johnson said. "I got to take it day-by-day."

Johnson's return couldn't have come sooner for the Northern Iowa product. He's missed every padded practice of training camp and Arians' frustration with Johnson was mounting every day.

"(It's ) killing him," Arians said. "There's no way a rookie is going to play in September and miss training camp. There's just no way in hell I'm putting him out there -- not in any expanded role of any kind."

Arians said Johnson and Andre Ellington are the foundation of Arizona's offense. Without both of them at practice for most of the last two weeks, the Cardinals weren't able to install packages specifically built for Johnson and Ellington.

"It's a pain in the ass when you got two guys that aren't out there practicing, and you got packages for them and you can't install them because it's not fair to the other guys because that's not their skill set," Arians said. "So you modify your practice and all your scripts to do something that's beneficial for all those guys."

This was Johnson's first "significant" injury of his football career. After tweaking his hamstring on Aug. 2, the rookie panicked a bit, unsure how to approach his comeback, the story said. With Andre Ellington also out, it put a damper on practices because they are considered the top two backs. Arians said he expects to get Ellington 20 touches a game but that also includes receptions so it looks like there will be plenty of opportunity for Johnson to be involved in the offense, too.