With regular right-back Joe Shaughnessy is suspended this weekend and Ryan Jack out for several weeks with a hip injury, Logan could be set to make his debut in tomorrow's League Cup semi-final.
Dons boss Derek McInnes said: “We’ve signed Shaleum on a deal to the end of the season and he’ll go into the squad for Saturday. He is a right full-back, he has good pace and energy. He also likes to get forward but is a very good one-on-one defender.
“He’s got good experience, he’s played a lot of games for Brentford but has been in and out of the team lately.
“I just felt, in light of Michael Hector staying at Reading, Joe Shaughnessy being suspended as well as Ryan Jack’s injury it was an area of the team we could do with strengthening.
“So, when the opportunity came up to say he was available, we moved quickly on it and we’re delighted to get him.
“He played on Tuesday so he’s match fit and has the experience to handle the challenges ahead of us.”
Logan told RedWeb: "I first knew of Aberdeen's interest earlier in the week and I can't wait to get involved.
"There are so many big matches coming up and obviously I want to get playing as quickly as possible.
"The fans can expect a player who gives 110% in every game and I would describe myself as an attacking full-back."