The past two years I have kept a running log of who the Cs workout, this is the list for this year.
P.J. Hairston SG 6/3 per twitter
TJ Warren SF 6/3
Marcus Smart G ? Per Jeff Goodman
Kyle Anderson F 6/3 per espn
DeAndre Daniels SF 6/3 per espn
Cleanthony Early SF 6/3 per Jeff Goodman
KJ McDaniels SF 6/3 per Jeff Goodman
Noah Vonleh PF ? per Jef Goodman
Xavier Thames G ? per Spears
Kendrick Perry PG ? per david pick
Russ Smith PG ? per adam zagoria
Chaz Williams PG 6/2 per Josh Newman
Doug McDermott SF week of June 12th per goodman
Nik Stauskas SG week of June 12th per goodman
Adrien Payne PF 6/5 per Goodman
Noah Vonleh PF 6/12 per Goodman
Kadeem Batts PF 6/2 per David Pick
Artem Klimenko C 6/11 per jay king
Semaj Christon G 6/2 per xavier hoops
Nick Johnson G 6/2 per xavier hoops
Bryce Cotton G 6/2 per Blakely
Deonte Burton G 6/2 per Blakely
Kyle Casey F 6/2 per Blakely
Reger Dowell G 6/2 per Blakely
Tim Frazier G 6/2 per Blakely
Clint Capela PF 6/5 per Le Clezo
Michael Dixon PG 6/4 per
Gary Harris SG 6/9-13 per Blakely
Jerami Grant SF 6/12 per goodman
C.J. Fair SF 6/12 per goodman
Aaron Gordon SF 6/12 per goodman
Walter Tavares C 6-13? per Blakely
Isaiah Austin C 6/12 per goodman
Sam Dower C 6/12 per goodman
Javon McCrea PF 6/12 per goodman
Daniel Miller C 6/12 per goodman
Luke Hancock SF 6/?? per himself
Nick Stauskas SG 6/?? per goodman
Geron Johnson SG 6/12 per holmes
Zach LaVine SG 6/13 per LaVine
Julius Randle PF 6/13 per Holmes
Jordon Clarkson PG 6/13 per King
Elfrid Payton PG 6/13 per king
Shabazz Napier Pg 6/16 per metro boston
Keith Appling PG 6/16 Holmes
Dave Dudzinski PF 6/16 Holmes
Jermaine Marshall SG 6/16 Holmes
Markel Starks PG 6/16 Holmes
Tyler Stone PF 6/16 Holmes
Chane Behanan PF 6/21 Greer
Jordan Adams SG 6/20 Forsburg
Jabari Brown SG 6/20 Forsburg
Markel Brown SG 6/20 Forsburg
Kyle Marshall SF 6/20 Forsburg
Xavier Munford SG 6/20 Forsburg
Devin Oliver SF 6/20 Forsburg
Niels Giffey SF 6/21 Forsberg
Glenn Robison III SF 6/21 Forsberg
JaKarr Sampson SF 6/21 Forsberg
Patric Young C 6/22 posted on his own Facebook that he was going to Boston the 22, no actual mention of the Cs (confirmed by King)
Rumored 2nd Workout participants
Smart
Gordon
Vonleh
Nick Johnson
1st RD Players Ainge has gone to watch Workout
Aaron Gordon 5/23 per Eric Pincus
Zach LaVine 5/23 " "
Marcus Smart