Arizona manager Chip Hale said before batting practice that there was a chance Tomas and/or second baseman Jean Segura would be scratched. Segura left Thursday's game early with a cramp under his left rib cage.
"We've got two guys who are a little bit in flux," Hale said.
Tomas took batting practice on the field but was scratched afterward. He is batting .270 with 30 homers and 80 RBIs in 138 games.
Segura was scheduled to take batting practice in the cage rather than on the field. Segura is batting .320 with 20 homers and 64 RBIs in 150 games. He also has 201 hits, five shy of the single-season franchise record set by Luis Gonzalez in 1999.
Jake Rill is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.