You have to be careful just looking at end of season stats sometimes. For example, Ervin struggled the first half of his season in the Ukraine, being shifted to SG and playing on a team with no shooters to spread the floor. Second half of the year he pretty much dominated.
Having said that, Trigg's resume looks decent, didnt have a great season last year but his last game was against the champs who are now in the Euroleague and he had 20, 6 & 4.
His performances in previous seasons in Europe suggest he is inconsistent but can produce big numbers, as he has a number of times in playoffs.
I like the fact that he has been signed year after year in Ukraine, that tells you he was seen as a good player in their comp. Of course, we dont know how well all that translates til he's on the court here!