"He's at home. He was at the airport yesterday, throwing up, diarrhea. He said, 'I can't get on the plane doing this,' " Yost said.
Escobar called earlier in the week, explaining that he couldn't obtain a visa for his wife in Venezuela because the office was closed until Friday due to Carnival.
Tejada was on the Dominican team that played in the recent Caribbean Series in Mexico. He also played 63 games this winter for Aguilas Cibaenas in the Dominican and hit .269 with seven home runs and 32 RBIs.
"He's played winter ball and only had five or six days off. We told him to go home, see if you can come Saturday. He was sick," Yost said. "It's not an issue. He's not going to be behind."
Escobar is also expected to arrive on Saturday. He played in the Venezuelan Winter League, hitting .340 with eight extra-base hits and 16 RBIs for Cardenales de Lara.
Everyone else on the 62-player training roster was in camp on Friday.