That's really about the end of what the Bulls got for Marquis Teague. Out of his low cost contract for next year, so low that even the vet minimum cap hold will only be around 600k less than what he's making.
Still, the Bulls got a shade more breathing room this season under the tax while opening up a tiny bit more cap room next season. I think we'd seen enough of Teague to feel confident with that trade. Teague just doesn't look like an NBA caliber player. A guy as young as he is who didn't show any real improvement over two years? Just not likely to get it done.
It's still early in his career. He'll still have a shot. I found him to be a likable, enthusiastic kid when I talked to him at media day the past couple of seasons, but he wasn't able to improve his jumper or finishing ability and remains a player with great speed, but not much else. Brooklyn will need to hope they can get more out of him than Chicago, and perhaps the trade will serve as a wake up call for Teague.
As for the Bulls, well they open up just a shade more cap room to pursue free agents next season. The Bulls would need to open up more cap room in order to pursue LeBron or Carmelo (Gibson or Noah would have to be traded as well as Boozer amnestied), and it doesn't seem like Melo's a Bulls guy or that LeBron would consider coming here.
Using cap space also means Mirotic can't come over, so the situation wouldn't be so appealing either as the Bulls front court would be down to just whomever is left between Noah/Gibson. In short, the Bulls will likely have no real money to pursue free agents. To open up more cap room than the MLE, the Bulls would have to amnesty Boozer and wait on Mirotic.
That combination leaves them with a very thin front court. That's just to get to the 12 million dollar range for a mid tier guy like Deng or Stevenson. In short, the Bulls need to either keep Boozer or bring over Mirotic so that they still have a solid group in the front court which means they'll have maybe seven million max left.
In short, while the Deng trade opened up some intriguing possibilities, it will be difficult to cash in on any of them in free agency. The Bulls have a better shot of pulling off a trade. The move of Teague probably doesn't help overly much with that, but Teague likely wasn't viewed as an asset in a trade for them, so a little extra cap relief they can offer someone may still help.