The world No. 25 had been scheduled to face Argentina's Leonardo Mayer in a second-round match. He lost to Chung Hyeon in the Australian Open fourth round in January before undergoing the surgery.
Also, American Taylor Fritz defeated Fernando Verdasco of Spain, 4-6, 6-2, 7-6 (7/1), Croatia's Borna Coric breezed past Roberto Bautista 6-1, 6-3 and Pablo Carreno-Busta of Spain, stopped Russian Daniil Medvedev 6-1, 7-5.
Former World No.1 and 12-time Grand Slam champion had a comeback to forget on the ATP Tour, losing in the second round against Taro Daniel.
He is making a cautious return to the ATP Tour after stopping his 2017 season following Wimbledon due to a right elbow injury.
In other action, current world No. 1 Roger Federer picked up where he left off, winning the four games he needed to defeat Federico Delbonis after their match was interrupted the night before by rain.
Stephens lost to Daria Kasatkina of Russian Federation 6-4, 6-3, and fell to 2-4 in matches this year.
Having lost seven games in a row, Krajinovic finally got on the board again with a hold for 3-1 in the second.
"I was grateful to be out on the court after surgery that quickly but at the same time just didn't feel good at all", he added.
Up to 7 courts, including the biggest matches of each day. "He's only going to get better from here", concluded the world number one.
"I was attacking when I had my chances and controlling most of the times the points", said Cilic.
"So I'm on a good run right now, and I try to maintain that, and you only maintain that if you respect every opponent".
In three tournaments prior to the Indian Wells Masters, he has reached the semi-finals only once.
"I'm still not strong enough to go play a match".