Luton have made their ninth summer signing following the arrival of winger Danny Green.
Notts County have signed Togo international Mawouna Amevor on a two-year deal.
Blackburn could face the possibility of a transfer embargo for failing to comply with the new Financial Fair Play regulations, according to the club's managing director Derek Shaw.
Last month Venky's London Limited, the parent company for Rovers, posted losses of over £27million with the club's accounts, due later this year, expected to paint a similarly bleak picture.
And, earlier in September, it was revealed Blackburn were far and away the biggest spenders on agents in the Championship as the club struggled to cope with their relegation from the top flight two seasons ago.
Speaking at a fans' forum hosted by BBC Radio Lancashire on Monday night, Shaw revealed that even promotion back to the Premier League could see the club hit with a fine once the new FFP rules come in.
"If we are promoted I think we'll have a substantial fine and, if we're not promoted at this stage, we'll probably have an embargo," said Shaw.
"It's a difficult balance because we've got to try to and change a team around that almost got relegated to a team that we want to get promoted."
Rovers have had a more prudent summer transfer window, allowing high-earners such as Morten Gamst Pedersen to leave on free transfers.
Shaw himself is not a fan of the FFP rules, and added: "It's very difficult for clubs who have come down from the Premier League with quite a number of big contracts that are in place, but we're working on it.
"I think there will be a lot of clubs creating a lot of noise over the next few months because nobody's really been hit with it yet.
"Clubs like ourselves and the Leicesters, and probably clubs like Middlesbrough, who have got big wage bills, won't be wanting transfer embargoes."