Team captains are always wondering if they will have enough players to create a lineup for an upcoming match -- nothing worse than defaulting a line when not enough players are available.   It would be ideal to spot these potential availability issues several weeks prior to the match.  Now at quick glance, the entire team can easily see if enough players are available for an upcoming match... they are even color coded with red, yellow and green (like a stop light).
Here are a few different upcoming matches and overall availability for these matches:
Match #3 is a green colored box with "9 of 8" available.  This team only needs 8 players for the match (2 singles lines & 3 doubles lines) and with 8 or more players available to play, we are green and good to go!
Match #4 is yellow colored since I only have 7 players available, but I need 8 to ensure I do not default a line.  Yes, time to click on that "button" to see who all I need to talk to about playing 
Match #5 is red colored with only 5 players marked as "available to play" and short 3 people... time to send out an "availability email" to get everybody to update their availability for this match to ensure we aren't defaulting lines.
Yes, you can click on any of these "x of 8 - buttons" and be able to see exactly who is available:
In the screen shot above, notice that Bill is "last resort" and Bob is unknown (no availability set) -- as team captain, I can click the "Request Avail on Checked" button and an email will be automatically sent to Bill and Bob asking them for their direct availability for this given match.   Both will receive a personalized email with all the match details along with buttons to click... "yes, available", "Not available" and "Last Resort" just like this:
Wondering if all your players are still available to play, yes you can send out the "Availability Email" to everyone on the team.... each email is customized for the person receiving it and shows that player previously set for their match availability.