"Apparently it affected one lung and he was wheezing a bit afterwards. His temperature stayed up for over a week.
"He is the sort of horse that if he is not feeling on his game, he can do what he did at Te Aroha. He was off his game, and though his temperature has come right and he's bright enough, he has put on an enormous amount of weight. I cut back his feed for that reason.
"He had his first gallop on Saturday morning and he'll gallop early this week and then I'll make a decision on whether he runs on Saturday.
"He needs to convince me he is fit enough. I have got to be 100 per cent sure or I won't pay up."
If Dawn Patrol does pass the test today, he will have to again satisfy Ritchie on Thursday morning before taking his place on Saturday.
"It's going to be a top field and it'll be a tough race," Ritchie said. "The next problem for me will be finding a rider because most riders have got rides in it and I can't commit anyone until I'm sure he will start."
The Te Aroha failure was the first time Dawn Patrol had finished out of the first three placings in six starts. Those previous efforts included two wins and three black type placings, including a second to Madison County in the Group 1 New Zealand 2000 Guineas (1600m) at Riccarton and a third to Emily Margaret in the Group 2 Wellington Guineas (1400m) at Trentham last month.
Meanwhile, Leith Innes will again ride Fiscal Fantasy in the Travis Stakes, with the petite 4-year-old mare set to be spelled after Saturday's race.
"She's been up for a long time, and really in each of her last three runs, I have kept thinking we won't go much further, but after a week, she keeps coming back," Ritchie said.
"But this will be it after Saturday. She can have a well-earned spell. She had her first run this season at Hawke's Bay [last October] and all her runs have been for good stakes and hard races.
"She keeps surprising me. I keep saying how small she is, but she's as tough as teak and keeps coming back for more."
The daughter of Skilled has picked up four wins and nine placings from 18 starts. She has been in the money every start this season and been unlucky not to win more.
"Really she should have won her last two, but this is another level up on Saturday," Ritchie said.
"She deserves a crack at it and the thing with her is if it rains a bit, it doesn't worry her, as long as it's not too much."
- NZ Racing Desk