Since Ritz will likely run a 5000 yet this season (or maybe several 3k-5k races) I will be the first to say this (I think).
Based on a 27:22 run off 13:50/13:32, it seems like a slamdunk that he should be able to go 13:05-13:10 right now if his form is sustained.
Keep in mind that I am not talking about what he MIGHT run, or what his lifetime potential is, or how much faster he MIGHT have been if he had stayed with Wetmore, or not gotten injured or not taken up the marathon. None of that, that has all been debated ad infinitum before. What I am talking about is what he can likely run right now based on this CONCRETE result.
I beleive he is better than 27:22 right now, based on the splits and the fact that he was competing in a championship race. In a "set-up" race I believe it is fair to say he is in 27:15 shape, better than that I can't be sure, but people have been saying that Bekele is in WR shape, so that would be 30 sec faster than the 26:46 that he ran. I think it is conservative to say that DR could run 7 seconds faster.
I was hoping that he would run the 10k at Brussels, but I have not heard anything about that so I am hoping he can get into 1-3 5ks in Europe still this season.
If you think about other people who have run near 27:22 and what they ran for 5k (Salazar - 27:25/13:11- same year; Bickford 27:37/13:13; Rono 27:22/13:08 - same year; Mamede 27:13/13:12 - same month; Kunze 27:26/13:15 - same year - 13:10 from '81).
I use these "old school" examples because back before we had WC every 2 yrs, runners would actually train for the European season and treat it as a big deal. They had National Championships that sort of interfered with running 3k-5k-10k several times a year in Europe, but they would generally do 5-10 races and their SB for 5k and 10k would usually be fairly even.
Anyway, based on these times I think Ritz should be able to go 13:05 at best (in the right race if his from holds) and about 13:12 at the worst.
Would be even better if he took a shot at the 10k AR. Knowing that he can do 27:22 he would just need to go out in 13:35 and take it from there. If he can maintain he would have the AR.