I'm a little confused. You are blaming him missing 3 games on being undersized? Name me 1 fantasy relevant RB that hasn't missed at least 3 games in a given season.
####, if you told me the RB I was drafting was ONLY going to miss 3 games, I would be thrilled. Runningbacks get hurt, it's what they do. As far as undersized? I don't see it.
Clyde Edwards-Helaire: 5 ft 7, 207 lbs
Dalvin Cook: 5 ft 10, 210 lbs
Aaron Jones: 5 ft 9, 208 lbs
Ronald Jones: 5 ft 11, 208 lbs
Kenyan Drake: 6 ft 1, 211 lbs
Miles Sanders: 5 ft 11, 211 lbs
JK Dobbins: 5 ft 10, 212 lbs
Maurice Jones-Drew: 5ft 7, 207 lbs
So to your argument, he literally is the same exact size as MJD and is within 5 lbs or less of all the other backs featured despite being between 6 inches or less shorter. He arguably has the best BMI / center of gravity / build of all those players listed who can get the job done.
But I will cede, because if I don't say he is undersized, then I would also be arguing that MJD wasn't undersized because he definitely was.
But I get it, we all have our preferences. I just think this guy is a stud and Andy Reid's offense is super complicated and given a little more seasoning, he will be a stud.