Thornton suffered a grade one medial ligament strain early in the first quarter and Hartlett was sidelined early in the second term after he succumbed to yet another hamstring injury.
Speaking in his post-match media conference, Ratten said the absence of Thornton and Hartlett well before the second half was telling in Carlton's overall result.
"If you lose one player in the first-half your winning chances go down by around 17 per cent, so we lost two, so I don't know what that percentage takes us, but it does have an impact there, but that's the way footy is," Ratten said.
"Do we call for the extra interchange? I don't know, but it's the first time it's happened to us, so you've just got to think on your feet and the only thing it does do is gas players … and maybe put other players at injury [risk].
"I'm not calling for it (an extended interchange), but when it does happen in the first half of the game, maybe that's something to look at."
Ratten said he heard North Melbourne coach Dean Laidley talk about the '17 per cent' factor.
"I've heard another coach speak about it, so [it's] plagiarism," Ratten said with a laugh.
"Dean Laidley actually spoke about it on SEN and I was listening to that and I knew it was getting up there, but it is a big stat.
"Teams have done it. Adelaide beat Port Adelaide with only two interchange [players] on there and even one, so teams can do it."
The Blues had other injury concerns with ruckman Cameron Cloke (knee) and first-gamer Steven Browne (hamstring). Ratten said Browne's tightness in the leg made it difficult to rotate players off the ground, which resulting in several Blues' fatiguing.
"Did we rotate enough? We had 57 rotations to their 64 and the boys (coaching staff) were talking about the rotations … but we had a ruckman (Cameron Cloke) on the bench and we had Steven Browne cramping on the bench," Ratten said.
"That makes it pretty tough to start throwing players around willy-nilly, so we had to look after his (Browne's) welfare to make sure he didn't get a hamstring injury in his first game of footy … Next week we've got three out, so it was not the easiest day."
