It's been a few years since I've played one of these ESPN market rate type fantasy games, but if it's anything like it was in the past, those prices should be dropping on injured players. Can't find anything on the site though that says the market value for players will increase or decrease over the course of the season.
IME, the best way to be competitive in these games is to adjust your roster to the schedule from week-to-week. Arsenal only played one match the first week, so I didn't pick any of their players. I thought Tottenham and Chelsea had favorable matches so I had at least a couple from each of those teams. However, I did miss the news of Ledley King's injury, but I replaced him today.
