So, according to everyone not within the Steelers Organization, Bryant is being shopped. Has anyone asked Bryant about this? If he is aware, he hasn't said a word about it. Is Colbert or Coach T aware of this? They haven't said a word either. I find it interesting how the media strikes up the rumor mill on their own, with no factual evidence or leads to back their claims. Speculations tend to be a lot like deer turds, all over the place, but no lead to where it's coming from.
The whole premise is stupid to begin with. There's very little in the draft that can be gained, by trading away a talent like Bryant. Beat writers tend to point at how his season began last year, and how he asked to be traded. Very little is said about how his tune changed and why he doesn't want to be traded after all. And while there hasn't been any talk about an extension, that doesn't mean there won't be one at all. The current focus is on Bell's contract. One would have to believe that any other contracts in the making, would be based upon how they handle Bell, and what Bell does afterwards. With Bell being the main focus this off-season, everyone else is waiting in line.
So why not trade Bryant? What worth do you put on a healthy WR with still untapped potential and a high ceiling? A 3rd rd pick? A 2nd rd pick? While there are some good WRs in this draft, do any of them compare to Bryant, right now, available in the 2nd or 3rd rd? Also, it speaks to this issue, the Steelers need help on defense, why hurt yourself on offense by taking away a talent like Bryant, going into his last year of his first contract? Why focus on an area that's already spoken for? By trading away Bryant, you're now left with Brown and JuJu, and very little to speak of behind them. If Brown gets hurt, are the Steelers supposed to put everything on JuJu's shoulders and still do fine as they are?
The way I see it, it's simply a bad deal. It's not as if the Steelers haven't been good at finding WRs over the years. In fact, they've been among the very best in the league over a 25 yr span doing so. But having to worry about a WR early on in the draft, a draft in which, they won't have a 4th rd pick, a draft where they need to find an ILB and a Safety, they'll be hamstringing themselves by having to settle for a WR that they might not have even bothered with in the first place, had they kept Bryant. And they're still not sure if they will be able to get Bell signed going into the draft. They might have to use one of those early picks for another RB.
The Steelers aren't idiots, they know they have to consider all possibilities during the off-season, to stay near the top, to give themselves the best chances to win it all. And when they don't (very rare for them to do so...) we call this a lack of priorities in the draft, the Steelers haven't drafted like this in a very long time, if ever.
So if there's a TL:DR to all of this: The reason you don't trade Martavis Bryant, is because you don't know what the future holds for Le'Veon Bell's return.
This offense is pretty much as good as it will ever get, with the current players projected to return, which would include Bell. And all of them are relatively young. They're in WIN RIGHT NOW mode, not "Let's re-organize and get back on top" Mode. They're too close to reaching their goal, to change an area in which none is needed. They've shown that they can finally get over the hump against the Patriots on offense, as long as the defense can uphold their end of the deal. There's not a better 1-2-3 at WR, than what the Steelers have right now.