For some reason, I hadn't really considered that referees would also have to be in the "bubble" for the NWSL Challenge Cup. It makes a lot of sense, but I just didn't consider it until I heard one of the commentators say it during the Utah Royals v OL Reign match.
This triggered the part of my brain that always comes out in tournaments...
How many games does this referee have under their belt before the final?
So I did what any reasonable person would do and put all of the data into a spreadsheet and started manipulating it a bit just to see what would come out.
There are currently six referees and nine assistant referees on board for the tournament. There have been 16 matches so far. This is how it breaks down for total assignments.
Note(s): I left out fourth official assignments. While they are a valid part of the officiating crew, it's somewhat of a break compared to being at the center. Also, it's entirely possible that any assistant referee could fill in at the center if absolutely necessary. However, USSF and PRO have started splitting the training at this level to have more specialized officials.
Based on the breakdown, it looks as though the assignors at PRO have done a pretty decent job distributing the referees around, with one exception:
Lukasz Szpala has been at the center of two matches involving the North Carolina Courage. While this isn't always an indication of anything, I would guess that we won't be seeing Lukasz at the center of the Courage v Thorns match up in the quarter finals.
Why is this?
Generally speaking, the assignors will try to avoid putting the same officials (especially the center) in games with the same team as much as possible. This prevents a few different things from happening.
The referee becoming the target of abuse/mistrust from the teams or coaches. You would be amazed at the memory coaches and players have and how quickly they'll pull up a "that wasn't a foul last week" when they feel like they've been hard done by a call. The more space you can give them between matches, the better.
It puts a fresh set of eyes on both the team and the game. From a referee standpoint, no matter how hard you try it's difficult to not pick up patterns of play from a team and be pulled into a false sense of security. At the PRO level, the referees do a non-trivial amount of preparation for each match, but if you've already seen a team multiple times it can sometimes be harder to see the forest through the trees.
It's the ultimate balance. As much as referees, assignors, and assessors try to bring across a consistent approach to calling the game, every referee has some nuance to how they call things. The more variety you can put into the rotation, the better.
There are seven matches to go in the coming weeks so it's possible that only one referee sees two games during that run in.
If I had to guess, it will be Karen Abt who has a quarter-final match and then the final or a semi-final. Out of the two referees that only oversaw two matches during the group round, I believe she's the only FIFA ranked referee. It's also possible that Danielle Chesky or Katja Koroleva don't see another match until the final as they are also FIFA ranked and both have experience in NWSL finals.
Maybe we'll get the ultimate gift and see the return of Christiana Pedersen.