I have found this:

Ep 522 is called Burned. The ep is about a woman who is being stalked by her ex boyfriend when her house, who she hares with her new boyfriend burns to the ground. Her new boyfriend ends up dead. The ex becomes a suspect. There seem to be some interesting twists in this one.

For instance, the fire was staged to get away from the stalker ex and so the woman and her new boyfriend could start a new life but something went wrong.

Ryan apparently owes a bookie Ten Grand from playing Texas Hold'em, who becomes a suspect and offers for the debt to go away if Ryan cuts him loose. He doesn't cut him loose but he does get in trouble for paying him the money while on duty. He leaves the case to go meet him and pay him.

Yelena is back in the ep. Shes back as a private investigator, but for how long, not sure
So this would ring after the ep with Ryan and the dodgy notes - remember when he said he had a few games and that was the payout. So it seems that because Ryan nips off to the pay the guy, and then H finds out, he explains that he can't help Ryan, but if had come to him rather than going alone, then he could have helped in some way.

I'm with you though Em - I've never taken to Ryan, even when he had the nail in the eye incident.

We also have:

Question: Got any CSI: Miami scoop?
Ausiello: Ryan lands in some serious hot water when Horatio finds out he used his connections to try to settle a gambling debt. Meanwhile, look for some major sparkage between Calleigh and Delko.
which all ties in with what I've said.