England's premier all-rounder, making his maiden first-class appearance since an operation on his left ankle in January, lasted only five balls on Wednesday before edging Kabir Ali to slip as Lancashire slipped to 196 all out.
But Flintoff refused to be disheartened by the setback.
"The ankle feels fine," he said on Thursday.
"I was probably a little eager and went after one I could have left. It's been a while since I've played, apart from Sunday, and I've been desperate to play some cricket again. I've been in the gym and training for the last 10 weeks so I was probably a bit nervous and eager."
Flintoff's rehabilitation programme after a bone spur was removed from his ankle has included regular running alongside former England physio Dave Roberts, but he still has some way to go before he can set a date for his return to bowling at full throttle for Lancashire and England.
"I don't know when I'll be back bowling again - it's very much day to day at the moment," admitted Flintoff.
"I started walking through my bowling a couple of weeks ago and I've been bowling for 20 minutes at a time in the nets at around 50-60 percent, but I couldn't say for definite when I'm going to be bowling again.
"I'm just pushing it more and more and seeing how I'm reacting to what I'm doing.
"I've been doing quite a lot of impact work with Dave. I've been doing a lot of hopping, jumping off steps and all sorts landing on my left foot just to get it used to me banging down on it again.
"Everything I've done so far I've responded well to, so it seems encouraging. I've only had one setback during this period when I had a slight problem with my calf on my right side, probably because it was compensating for my left leg, so I got a bit of a twinge in there, but it's not been anything serious."