I'm going with Boston Card here. In the last couple weeks I've rewatched several of Mac's games last season. And I had missed several of them, so I was seeing them afresh--and he looked less scary than he had the year before. I kept thinking, "Okay, he's going to break this one," but then he wouldn't.
He may have been a blink slower after the injury. His recent 4.48 hints that he may have gotten that blink back.
When/where was this 4.48?
The 4.48 noted by Mick above was somebody's guess as to what he would run, apparently not an actual time.
Of course it could also be an actual time, and would be about my guess for him as well.
This past year is interesting on McCaffrey's production, and perhaps a testament to the power of expectations to colour our perception of what we see.
He had a better yds/carry in 2016 than in 2015 by 6.34 to 5.99.
The number of big plays is a small enough number that it can be rather random, but it is directly related to what people are comemnting on.
Overall, it looks as if his percentage of big plays held remarkably steady, despite fewer carries overall and thus fewer big plays.
10+ yd runs: 2016 = 39 (15.4%), 2015 = 56 (16.6%)
20+ yd runs: 2016 = 14 (5.5%), 2015 = 19 (5.6%)
Both years there were some games where McCaffrey seemed considerably less effective. In 2016 that seemed to be primarily due to injury.
In 2016 McCaffrey was more steady on a game to game basis - with lower highs and higher lows.