Hughes expressed disappointment over his former captain's desire to return north of the border but said Ferguson's attitude had left him with little choice but to recommend the pounds 5m deal.
Hughes said: "I spoke to Barry before the weekend and I was a little disappointed with what I got back, so on reflection I thought it was best for Barry and ourselves if we all moved on. Once Rangers got to a proper and right level in regards to the transfer fee I recommended to the board that they should let him go. Barry is a good player but I have got other very, very good midfield players. We have just been able to bring in Robbie Savage so that more than compensates for Barry's loss."
Hughes, a former Chelsea player, is relishing the prospect of measuring his own side's improvement against Jose Mourinho's men, who thumped Rovers 4-0 in the Welshman's first month in charge back in October. That game saw the debut, as a second-half substitute, of Arjen Robben, who has gone on to encapsulate Chelsea's own improvement into a team seemingly destined to claim the Premiership title.
Hughes said: "You want to match yourselves against the best and this will be a great test of how far we have come. We think we have improved but they have probably moved on as well from that point which is a worry. Our trip down there was the first introduction of Robben to the Premiership. He only played for 20 minutes but he made such a big impression in that short space of time."
Hughes has a fitness doubt over his striker Paul Dickov who missed Saturday's FA Cup fourth-round win over Colchester with a nagging groin problem. Dickov will undergo a late fitness test before Hughes finalises his line- up for a game which he hopes will put even more space between Rovers and the Premiership relegation zone.
"This is what the Premiership is all about, when you play teams who are as good as Chelsea," Hughes said. "They are a really exciting side to watch and it will be a big test but I think there will come a time where Chelsea are not quite at the level they have been at all season. We hope that time will come [tonight] and that when it does we are able to capitalise upon it."
The striker is the only major doubt for Hughes, who will pin his faith in his current crop of players after losing Javier De Pedro as well as Ferguson during the transfer window.