I think Johnston pulled up and did not follow through. But the majority of tackles like that are typically yellow card worthy.
After re-watching it, I'm okay with the yellow card. She may have not had the follow through, but the way she went in could still be called "reckless." What I do question though was the foul called on JJ earlier in the game (around the 20' ?) where it looked like Cruz actually went into JJ's head with her elbow...that was not a foul on JJ, imo. My biggest problem with the referee though was that she needed to get out of Lloyd's way!
The three back might give Ellis an interesting change of pace against any team if she is willing to break up her back line. If she wanted to bring Press at 60 minutes in for either Krieger, Klingenberg, Dunn or Heath she could go 15 to 20 minutes with Morgan, Lloyd & Press, then replace Morgan or Lloyd with a defender and finish the game with a four back. Of course whoever ends up at the wing backs has to defend to make it work but it would force the other team to make a big defensive shift for key minutes in the middle of the match and then switch back.
I like the fact that our forwards have shown up so far in 2016 (albeit against Ireland and CR). Lloyd (sorry, I'm counting her as a forward) and Morgan have multiple goals and assists, while Press has scored a goal and assisted on another in limited minutes. Heck, even Pugh has a goal. I've always said, if the US wants to win the Olympic tournament their forwards have to show up this year. So far so good.
What is the difference between O'Reilly taking the ball wide and crossing to a teammate, Dunn just taking the ball inside looking for her own shot every time?
Some in-depth stats for the game: http://rpubs.com/AMJ/concacaf-olympic-qualifier-2016-usa-crc-021016 Looks like we'll have CAN and MEX stats shortly.