Outfielder A.J. Pollock, who was called up Wednesday, was optioned back to Triple-A Reno.
Kubel's wife, Blake, was scheduled to have labor induced next Thursday, an off-day for the team. However, Wednesday morning she began to go into labor.
"I really wasn't thinking about it so it caught me off guard," Kubel said.
Blake texted her husband a couple of times, but the noise his text alerts made did not wake him. Finally, she phoned him at 5 a.m.
Kubel then woke senior director of team travel Roger Riley, who got Kubel on the next flight to Phoenix while Blake drove herself to the hospital.
Kubel landed in Phoenix and took a cab to the hospital. He walked in at 11:50 a.m. and his daughter was born seven minutes later.
"We're very excited," Kubel said.