His swing coach, Rick Smith, described Daly as being in a "toxic state" after 88 in the Buick Open, which Smith attributed to a massive weight loss, not enough sleep and the wrong kind of diet.
Whatever the case, it led to Daly feeling as badly as ever about his golf.
"The last two weeks have been the first time in my career I didn't think I could win," Daly said. "I don't have the feel I used to have. I don't have the confidence. I just don't have it. I've thrown in the towel and shot 82 when I quit. But I didn't quit this time. It was a weird feeling."
Daly hit two balls out-of-bounds on the par-5 first hole his 10th of the second round and took 10. He wound up shooting 51 on his back nine for 16-over 88. That was one shot less than the 89 he had last year at Royal Birkdale in the wind-swept British Open.
Smith said he followed him along Warwick Hills and almost didn't recognize him.
"I saw a guy I didn't know existed," Smith said. "What I saw today was scary. It was a literal disconnect. He hasn't eaten or slept in a week. His body needs food, and it's going to the muscle, and the muscle is breaking down to the point he's in a toxic state."
Daly says he has lost over 80 pounds in the last four months after having Lap-Band surgery, in which a tube place around the top of the stomach helps control the appetite. He was eating only 1,200 calories a day, but now says his intake is about 600 calories daily.
Daly said he weighed himself this week at 205 pounds.
"He's gone through it so quickly, faster than most," Smith said. "He hasn't felt well, he hasn't slept. He's starving himself. His doctors says if he doesn't have 80 to 90 grams a day of protein, he'll be in trouble. He needs to eat the right food and get himself back so he can even play golf. Looking at his swing today, it was irrelevant."
The PGA Tour suspended Daly for six months dating to November because of various off-course incidents, including a jailhouse photo of Daly with his eyes half-closed after being taken to a cell to sober up in North Carolina.
He has played mostly in Europe this year as he tries to qualify for the "Race to Dubai," but after a runner-up finish in May at the Italian Open, Daly has made little progress. His recent trip took him from the BMW International in Germany to the French Open, to the Scottish Open and British Open, then to the Canadian Open and the Buick Open.
The two-time major champion tied for 27th in the British Open at Turnberry, then he played the next two weeks on sponsor exemptions. Daly said he doesn't want to take a spot from someone else in the field if he continues like this.
Daly's career is littered with big numbers, such as the 18 he took on the par-5 sixth hole at Bay Hill. His confidence has fluctuated along with his weight.
"This is different," Daly said. "I can't control my hands like I used to. I have no clue where it's going. I just don't have any feel, and it scares me. This is the most down I've ever been with my golf game. I'm working my butt off, doing everything I need to be doing, and nothing is going right on the golf course."
Daly said he would see his doctor in Florida next week, then decide whether to play in the PGA Championship at Hazeltine. Daly's career took off in 1991 when he won the PGA Championship as the ninth alternate. He later won the British Open at St. Andrews.