It is the summer of 2014. Jared Sullinger has recovered fully and progressed so that some fans think he is a potential double-double starter, but some fans still doubt he is a long-term solution as a starter. The team's first round pick from 2013 doesn't look worthless, but is still all about potential and not someone who looks like he's definitely ready to start next season. Brandon Bass will be a $6.9m expiring contract. Jason Terry will be a $5.45m expiring contract. If they are both still Celtics, that is.
Imagine that a team has a big contract guy who is entering the final year of his contract and it looks like they will lose him to free agency, so they want to trade him so they don't lose him for nothing. It's probably unlikely they will be available, but players making $15m-ish with a year left at that point include Lamarcus Aldridge, Marc Gasol, and Kevin Love (if he intends to exercise his ETO).
Ignoring for the moment the question of how likely it is that a player of that quality becomes available, does a package of Sullinger, the 2013 first round pick, the 2014 draft pick, and expiring contracts give the Celtics enough assets to have a shot at winning a bidding war if an All-Star caliber player suddenly becomes available?
Good question, although there are really too many unknowns to give an answer. Depends on Sully's performance, and the potential of the '13 pick, and where the '14 pick ends up.
If you're thinking about trading nickels for a quarter though, a couple of recent benchmarks would be the Harden trade, the Howard trade and maybe the Carmelo trade.
OKC received a solid starter, a rookie with potential and two 1st round picks. One of the firsts has a good chance of being very valuable.
ORL received one solid role player, one high-potential rookie (Vucevic), three 1st round picks of middling value and a large trade exception.
DEN got three legit but not "star" guys (Felton, Chandler and Gallo), one of whom still had star potential, and a 1st.
So, to me it looks like the offer you are talking about is below those. Now, if you add another asset (Bradley) or pick, I think you actually get close. If you add Rondo I think our package would beat any of those.