Johnson, however, elected not to attend the team's mandatory minicamp as he enters the final year of a contract which pays a base salary of $1.88 million in 2018.
"I don't think there is any question David is one of our core players and someone we look forward to having a long-term future with," Keim said, via Darren Urban of the Cardinals' official website. "[It's] no different from in the past when we've rewarded players like Pat Peterson, Chandler Jones, Larry Fitzgerald, Carson Palmer, just to name a few.
"There's no doubt in my mind moving forward that we will keep a positive outlook and again, look forward to rewarding him just like we have players in the past."
The 6-foot-1, 224-pound Johnson is widely regarded as one of the NFL's elite running backs, and he is a productive weapon as a rusher and receiver.
Johnson missed 15 games with a wrist injury in 2017. However, he exploded in 2016 with 1,239 yards rushing and 16 touchdowns on 293 carries, averaging 4.2 yards per carry, and 879 yards receiving and four touchdowns on 80 catches to earn first-team All-Pro honors.
Entering his fourth season and fully healthy, Johnson eyes a 1,000-yard rushing and 1,000-yard receiving campaign , and he is capable of achieving the benchmark.