Teimana Harrison had to come off after just 31 minutes in the 22-21 defeat to Sale Sharks at cinch Stadium at Franklin's Gardens, while Karl Wilkins was withdrawn during the second half.
Ludlam could possibly be available for Saints this weekend, as he is not named in the England squad to face Wales at Twickenham on Saturday, but his recovery is ongoing.
Other back row options for Saints against Exeter include Alex Coles wearing the six shirt and perhaps appearances for players such as JJ Tonks and Ollie Newman.
But assistant coach Matt Ferguson says there is still plenty of assessment ongoing and he is refusing to rule out the likes of Ludlam, Harrison and Wilkins just yet.
"We got a couple more dings last weekend," Ferguson said.
"The beauty of going from a Saturday to a game the following Sunday is the extra recovery and planning time, and there is nothing significant enough to rule anyone out just yet.
"I did notice that Dows (Saints forwards coach Phil Dowson) was looking for a gum shield this morning so I don't know what you can read into that...
"There are two or three clubs struggling in the back row, particularly at the moment with internationals, because most teams tend to have their best players in the back row.
"We've had a planning day today (Tuesday) and we'll get out on the grass tomorrow and have a look at the decisions we've got to make around that area.
"Let's hope it's not Mikey Haywood in the back row because our lineout won't be functioning very well, will it?
"There's lots of options and we'll have a look and see what happens with Karl Wilkins, Tei and what happens with Luds.
"The good thing about it is that I can't definitely say 'that player is out for this week', it's soft tissue issues and bangs.
"Karl Wilkins got a bang on the rib and that can be incredibly uncomfortable but it tends to go as quickly as it comes.
"Luds is down with England doing some of his rehab and they're training later today so we're waiting for an update on him.
"We've got boys who can play in the back row and there's one thing for sure - there will be a highly motivated group going out there on Sunday.
"We've just got to make sure we match our physicality with our accuracy."