The Bill's do have (hypothetically) good depth at the position. Much of this is based on the limited exposure we saw of them last season. But forgive me for doubting their upside, aside from Stevie, there is no top-level talent in that group. Chan said as much when describing board favorite Roosevelt this past week.
Nelson lacks speed, you'd have thought Easley would contribute this year but I'm not even counting on him making the team, and Jones could be good but who really knows?
IMO, holding onto Lee is the prudent move, especially with all the talk regarding how Chan plans to integrate him more into the offense. If he is playing well and the Bills are winning, you keep him. If he is playing good and the Bill's are losing, the price for a WR on the contender could go up due to injuries. Then, you deal him.