The former Stuttgart defender played for Ipswich in a trial match last Monday and made an impression but Kevin Blackwell has moved swiftly in an attempt to conclude a deal and the centre-half is now set to undergo a medical.
The 27-year-old began his career with Benfica before spells in Germany with Hertha Berlin and Stuttgart. He then returned to the Portuguese Super Liga with Maritimo last season.
Marques said: "Leeds is a big club, it's really a Premier League club and I believe that Leeds will be in the Premiership again. I had some difficult times after Germany, but I think England will be a new start for me.
"I think it will be very interesting for me to play in England and I believe I have a lot to offer," he told Leeds' official website.
He could now play some part for Leeds in tomorrow's friendly against Celtic in Glasgow.