After throwing an 86-pitch bullpen session on Tuesday, Darvish was feeling good enough on Wednesday for Rangers manager Ron Washington to declare the right-hander ready to return from neck stiffness that sidelined him for two weeks.
Darvish, who was placed on the disabled list retroactive to March 21, will work the series finale on Sunday against the Rays and right-hander Tanner Scheppers will be pushed back to Monday against the Boston Red Sox.
Darvish, who led the major leagues with 277 strikeouts last year. was scheduled to start on Opening Day but developed the stiff neck during spring training and last pitched in a game three weeks ago.
The 2013 American League Cy Young Award runner-up finished last season with a 13-9 record and a 2.83 ERA.