Rest of Season stats are a work in progress. These numbers take all available Statcast data for each player, weights it by season, and regresses to the mean. Projected inning totals and plate appearances will, hopefully, be worked into the formula at some point in the future. For now you will have to settle for rate stats. You can plug in your own innings totals and plate appearances by making a copy of the spreadsheet and typing in the green columns.
Estimated xStats for 2017
Last Updated 3/18/2017
These numbers are calculated by giving the 2015 batted balls a weight of 0.92 and 2016 batted balls a weight of 1.00. All batters are given 600 PA by default and all pitchers 150 IP. You can make a local copy of these sheets by pressing "file, make a copy." When you do so, you may edit the yellow/green columns in each sheet to scale the numbers up or down for each player. I advise avoiding all players with a sample size under 100, and to be suspicious of anyone with a sample smaller than 200 or 300.