Well, not exactly. Yes, Tamari has played the entire season knowing one of every opponent's primary goals was to get her into early foul trouble so that she has to play with a lot less aggressiveness and confidence for as much of the game as they could dictate. But even though it was true that Key had to take it down a notch or two once she got some fouls, Tamari always knew that Keyen, an uber-seasoned veteran, had her back.
For a star player who is under a lot of pressure to help her team win games, there is a palpable difference between going to the bench for a bit KNOWING your mature backup is likely to hold down the fort while you're out, and going to the bench HOPING your far less experienced backup can get it done.
I'm not saying Emily and Karo can't get it done, but the new reality of not having Keyen to lean is almost certainly going to affect Key.