Big things were expected from McKinnon last year after he left Minnesota to join coach Kyle Shanahan's RB-friendly offense in San Francisco, but a torn ACL suffered just before Week 1 ended his season before it began. A healthy McKinnon possesses a wealth of athletic gifts and showed flashes of power, speed and receiving skills with the Vikings, but his lack of experience as a running back (he was an option QB in college) has always restricted his vision and ability to set up blocks. Shanahan has a knack for scheming guys open and getting them the ball in space, so McKinnon's flaws might not be as big of a limiting factor with the 49ers. What will limit his ceiling is the addition of running back Tevin Coleman from Atlanta, as well as the continued presence of Matt Breida, who totaled 1,075 scrimmage yards last season. McKinnon still seems to have a place in the team's backfield plans (San Francisco allowed his 2019 salary to become guaranteed rather than releasing him before April 1) but even Shanahan's system will have trouble finding enough touches for three running backs. McKinnon was in danger of being the odd man out even before his preseason knee issues cast his Week 1 availability into doubt. It's no longer clear when or if he'll be ready to play.

McKinnon showed flashes of upside last season in a backup role for the Vikings behind Dalvin Cook and eventually Latavius Murray, highlighted by career highs in rushing yards, catches, receiving yards and TDs. While his 3.8 YPC wasn't all that impressive, McKinnon performed well enough on the ground that the 49ers snapped him up in free agency to replace Carlos Hyde, inking him to a four-year, $30 million deal. McKinnon's raw athleticism has always been his calling card after a big combine catapulted the converted college option QB into the third round of the 2014 draft, and he's finally begun adding football skills to his speed, power and burst, honing his craft as both a receiving option and pass blocker. He still lacks the vision and patience as a runner to take full advantage of his gifts, but moving into Kyle Shanahan's offense drastically altered his ceiling. Unfortunately for the 49ers, the plan fell apart shortly before Week 1 when McKinnon suffered a torn ACL during practice. Breida and Alfred Morris are now expected to split work in the backfield.

McKinnon saw a career-high 202 touches last season thanks to Adrian Peterson's inability to stay on the field, but he wasn't able to do much with the added workload as his YPC plummeted in a larger role. The Vikings' issues on the offensive line certainly played a role in that performance, as the converted college option quarterback is still relatively inexperienced as a runner, and his struggles finding and exploiting holes were exacerbated by a line that couldn't create them consistently. McKinnon's speed and elusiveness still flashed on occasion, mainly as a receiving option, but the Vikings made it clear that they don't view him as a long-term answer when they signed Latavius Murray and then drafted Dalvin Cook in the second round. Now buried on the depth chart, McKinnon may struggle to find snaps in 2017.

Even on a team with Adrian Peterson, you wonder why McKinnon doesn't get additional reps. He averaged over six yards per touch last year and secured 72 percent of his targets, looking notably improved from his rookie year. Ball security has never been an issue here, as McKinnon doesn't have a fumble as a pro. Peterson has been remarkably durable for most of his career — running style be damned— so McKinnon might be limited to lottery-ticket and stash-and-hope status for 2016. But he has the look of someone who could be an instant fantasy difference-maker if he were forced to start at any point this year.

A third-round draft pick last year after a jaw-dropping Combine performance, McKinnon was expected to serve as little more than Adrian Peterson's rookie understudy. He suddenly found himself in the spotlight, though, when Peterson was suspended and Matt Asiata proved to be little more than a short-yardage specialist. Somewhat undersized at 5-9, 208, McKinnon was an option quarterback most of his college career at Georgia Southern, and he still needs polish as an running back. He can flash outstanding speed and elusiveness in space, along with the burst to explode into the hole, but he lacks the vision to consistently find those holes and has trouble at times turning his gym strength into running power and broken tackles. He improved in those areas as the year progressed before a Week 12 back injury ended his season. With Peterson back this season, McKinnon will return to a depth role, but more time spent learning at the feet of one of the greatest backs in NFL history can only help his development.

McKinnon's impressive measurables at the NFL Combine – including 32 bench-press reps, which led all running backs, and a 4.37 40 time – boosted his draft stock enough to entice the Vikings into utilizing a third-round pick to secure his services. After running for 2,867 yards and 32 touchdowns while splitting time between quarterback and running back (but mostly running back) his last two years at Georgia Southern, he should have a chance to beat out the singularly unexciting Matt Asiata for the right to back up Adrian Peterson. At 5-9, 208, McKinnon will likely have to bulk up some before he can handle every-down NFL duties and is very raw as a receiver, but he's a tremendous athlete who can make things happen with the ball in his hands.