It's got to be the draft, and we now see this was CB's intention from the start. This draft appears to be one of the deepest in memory and teams will be able to get pretty good ones even in the 4th round. So I expect the Colts to draft one in the 2nd, and I'd be absolutely SHOCKED if they don't. This will be good enough to become WR2 in this offense, and will make a good compliment to Hilton. I would expect one with size, ie. Higgins, Mims, Claypool, Pittman, etc. to be the guy. They already have two smaller, speedsters in Hilton and Campbell. Pascal is bigger and this would be the compliment to that.
It just makes sense to me that you go where the strength is in the draft and cover the weaker with FA. The DT's in this class are strong, so that makes the Buckner trade an outlier, but I don't believe Ballard had him targeted in any way. I think this opportunity just came along and Ballard thought it too good to pass up, and I would agree with him. I would also expect them to grab a TE and an OT.