"As sick as I felt, I almost feel worse because I didn't get to see the results I wanted to see," Halladay said. "I guess you just have to be patient and let it do its thing. There are things you can control and you worry about that."
Nothing has gone according to plan for Halladay this spring, a time when all eyes are on his prized right arm. He believes he can still be ready to pitch April 3, the second game of the season, with two more spring starts. He is aiming to pitch Saturday, which is contingent on mustering enough energy to throw a bullpen session Wednesday.
After that, Halladay should pitch in one more Grapefruit League game before camp breaks. His goal is to reach 75 pitches Saturday and 90 in his final tune-up. That, he said, should enable him to near 100 in his season debut.
"But if it doesn't go exactly that way," Halladay said, "I'm sure there are other ways to look at it."
The Phillies could push Halladay back and maybe start him in the fourth or fifth game of the season to provide more preparation time. While he is confident in his readiness, another setback could force a further delay to Halladay's 2013 season.
Beyond the sickness, doubt lingers because Halladay was ineffective before. Both Halladay and his pitching coach, Rich Dubee, have claimed to see progress during side work. But the 35-year-old righthander has pitched a combined 32/3 innings in his last two starts and his fastball velocity has cratered.
Scouts noted slight improvement during Halladay's brief, one-inning outing Sunday. But the sample size was too small for definitive evaluations. And Halladay himself has admitted the greater test is deeper in games.
"I saw better arm slot," Dubee said. "Not on a consistent basis, but more often. It was more impressive [that] he was able to get that arm slot with nothing in his body and no legs at all. That was encouraging."
Even on Tuesday, Halladay said he was "a little bit weak and jittery" just from doing some exercises. He vomited Sunday after his inning.
"Once my heart-rate got going, it intensified everything that was going on in there," Halladay said. "It was going to come out, one way or the other."
Halladay said the illness began Friday but improved Saturday with medication. He arrived at Bright House Field on Sunday morning and ate breakfast in the clubhouse. Then everything went wrong. "I didn't know which way I was going," he said.
The pitcher insisted on starting because he wanted to implement the changes to his mechanics and arm slot from his disastrous March 12 outing against Detroit that raised every possible red flag.
Plenty is riding on Halladay's ability to adapt.
"I feel like it's there," Halladay said. "I've made the strides I need to make. But I really haven't gotten to test it. That was really the most disappointing thing about it."
If his body cooperates, the chance will come Saturday. And everyone will be watching.
Contact Matt Gelb at email@example.com. Follow on Twitter @magelb.