Realistically, 3rd. Don't see how he beats Mo and there is likely at least one other guy who is just plain old better than Ritz is.
However, I certainly think the stars could align and he get's 3rd. I disagree with the posters who say he should make it a fast race. Ritz is tough, but his best chance is to hope its fast from the gun and not because of him.
Here's what needs to happen for Ritz to medal.
Decent pace where Ritz doesn't need to lead a step through 8k (call it 27:30 pace). At 2k, a pack of 4 break off at likely 4:00/mile pace or thereabout, Ritz maintains contact. With 600 to go one of the 4 (unlikely Mo) tries to break it open. Ritz, now 10-15 meters back, starts to close (maybe at 60sec pace at that point) but actually loses 1.5 seconds over the next 200 meters on the top 4 guys likely running sub 57 pace from 600 out.
By 300 to go, 1, maybe 2 of the top 4 begin to crack when one of the 4 (again, not Mop) takes the lead and drops it down to 55 sec pace, trying to drop Mo before the final 100-150. Ritz starts catching up.
With 150 to go, Ritz passes #4, Mo has already taken the lead, and is now 50 meters ahead of Ritz. Its a race for 1st (at lest until the last 50) and the guy in 3rd is coming back to Ritz.
Ritz, realizing he can grab a bronze, finds a gear he didn't realize he had in the last 75 or so and with 15 meters or so to go, passes the dude for 3rd. He closes in 1:27/57 and the guy he beats for 3rd runs 1:28.5/60
This is the scenario (or something very close to it) where Ritz medals.
He needs
1) a fast race that isn't ridiculously fast until the last 2l (i.e. no sub 13:00 last 10k. No sub 27:00 time. More like 27:20-35 through 8k)
2) someone to break the race open with 2k to go, and then someone else to try and take it to Mo with 600 to go.
3) He needs all but 2 of those in the break to crack as he comes up on them over the last 300
Best, and in my opintion, only way. But I could definitely see it happening.