West London Sport revealed last week that Angel was being brought in as cover while Darnell Furlong is out injured.
Rangel, 35, is a free agent, having left Swansea City when his contract expired this summer.
He spent 11 years with the Welsh club, making 328 league appearances and playing a key role in their climb to the Premier League.
Rangel, who played seven times for Swansea in all competitions last season, has been invited to train with the R’s, who expect to be without Furlong for at least three months.
Furlong, who missed much of last season with knee trouble, suffered another knee injury during a recent pre-season friendly against AFC Wimbledon.
This post was last modified on 13/08/2018