There's some mythology about Douglas some have. He had one very good Super Rugby season in 2014, and that's it. He was worse, way worse, than Horwill against the BILs and Horwill got panned. His international form was poor, overall. He was overlooked for the limited and departing Timani, it was that poor in 2013.
And to put that 2014 into perspective, he was a cog, yes a key one, but a cog into the dominant Tahs pack, which was the best pack in the comp. He wasn't the standout lock either, that was Potgeiter.
Douglas has gone to Leinster, and then gone poorly. Couldn't even make the starting side. Then got injured.
Putting him in the pedestal that some have, well, you are more than likely waiting for disappointment should he come back.