"Everyone knows we needed to look at left backs next season with Nigel Winterburn unfortunately retiring and at 39 you have to accept he can't go on forever - though sometimes he looks 29, not 39," says Glenn.
"Nigel's goal now is when he leaves West Ham in the summer he does so in the Premiership, which is the wish we have all got for ourselves."
With Nigel currently recovering from a wrist operation, and out for some weeks, Rufus' arrival was a timely one.
"It was a good deal to get him and I am hopeful that he will have a successful two and a half years with us," says Glenn.
"We have seen what Rufus can do and I would expect him to continue to make an impression on the club.
"He, along with one or two others, was a player we had been looking at. I knew what we would be getting with Rufus though I didn't expect to be able to make a move until the summer.
"But we got some indication that there would be a possibility that we could get him from Fulham in this transfer window just gone and I decided to act.
"We had to move fast; it was a really close call in terms of getting the signature for 12 o'clock and available for that game against Liverpool.
"He has taken a gamble, which shows you the sort of person he is - he could have stayed in the relative comfort zone at Fulham because we have a greater fight and a bigger challenge.
"But he wanted to take it up - and he knows he will be competing with Nigel again when he is fit, though it is virtually impossible for Nigel to play two games a week.
"Rufus plays with great energy, plays with the right amount of aggression, and likes to get close to the player he is playing against to get underneath them and get tackles in.
"Our fans certainly like players like that and you only have to see how they respond to Nigel Winterburn when he is chasing and closing down."
He made his debut against Liverpool, playing his first full game at Leeds; now, he has a full two weeks to really 'bed in' with his new colleagues.
"Rufus is a decent defender who wins challenges, and he has got enough ability to get himself forward and into dangerous situations in the attacking third to deliver decent crosses," says Glenn.
"Now we have got Les Ferdinand at the club we can start putting crosses into the box again with a fair chance of scoring some goals.
"Rufus has a decent left foot, I liked his attitude when I met him, and before signing him I asked a lot of people about him.
"Roger Cross has worked with him at QPR and he has played there with both Les and Trevor Sinclair."
The left back slot has been of some concern for Glenn for quite a while - especially as Vladimir Labant was unable to make the position his own following a £900,000 move from Sparta Prague last season.
"Unfortunately for Vladimir he didn't settle as we had hoped he would which is why he is back at Sparta Prague on loan," says Glenn.
A summer move for Olivier Bernard at Newcastle fell through, and he adds: "With Bernard we couldn't secure his services in the manner we thought we could have, and when we found out that he was still Newcastle's player, legally we withdrew from that situation very quickly - which was the right thing to do.
"It was important that we found a player that has good experience of the Premiership, and Rufus has 'seen off' two left backs at Fulham because Jean Tigana bought Jon Harley for £3.5m from Chelsea, and Wome, a Cameroon international from Italian football, and Rufus managed to keep hold of the shirt at Fulham.
"That suggests he is a fighter - and just the sort of character that we need in our current situation when he could easily have seen out his contract at Fulham in relative safety.
"It is tough times but this is when you find out about your players' characters, if they are made of the right stuff, and will they stand up and be counted in a pressurised situation."
Glenn has no qualms about Rufus' age - he is 33 - and explains: "I think there are a lot of players in their early 30s now playing some of the best football in their careers.
"We have watched Rufus lots of times this season and he is still going as strongly as ever.
"He has a solid family background, with a wife and two children, just the sort of background I like them to come from so you know they are going home to rest and I was very positive about him signing."