Texas put right-hander
Darvish had been scheduled to start Monday's opener against Philadelphia until he had neck stiffness two weeks ago.
Harrison, last year's opening-day starter, pitched in only two games last year and had a setback early in camp because of stiffness in his neck and back.
The Chicago White Sox finalized their 25-man opening-day roster by putting infielders
Beckham, Chicago's opening-day second baseman from 2010-13, has not played since March 14 because of a strained muscle on his left side.