The Scot said: “I had no issues while training, felt fine, did some gym work Friday, no problem, and then I woke up about 3 in the morning, felt pain in the groin, not on the side I had my surgery, and when I got out of bed I struggled quite a bit to walk.
“I’ve no idea what I did. It’s one of those freak things. Each day it has gotten progressively better, but it’s not enough. I have not practiced since Friday.
“I’m really gutted. This is a place I have done so much training over the years. It’s like my second home. Last time I played here was 2016 and so much has happened.
The Scot, who has won in Miami twice in his career, has only played three events this season, reaching the final in the Biella Challenger event.
Murray was also knocked out in the first round at Montpellier and in the second round at Rotterdam.
Harris, ranked 52 in the world, would have been a tough opponent for Murray, but one the former world No 1 wanted as part of his warm up for SW19 this year.