The Steelers gave him a draft round tender which means if he gets an offer and they don't match it they'll get a 3rd round pick as compensation. With Cortez Allen and Curtis Brown showing promise last year, perhaps Keenan becomes expendable for the right price? That extra 3rd round pick would be nice.
Having said that, I think in the end he sticks around for at least the 1 yr. tender but if an offer comes through on him I'm sure they'll at least look at it. You'd be foolish not too IMO.