It depends on the cap. Right now, the Trail Blazers are projected to be about $16 million under it, which is the difference between Aldridge's '20-'21 salary and the combined total of Hood's and Hezonja's.
They quickly moved to attempt to shore up "SF" though and Ariza played well (unsustainably so, granted). In free agency, they'd likely be left with lesser options like Harkless again, Carroll or Robinson.
They've always been high on Collins and given that he's a theoretical fit next to Aldridge and unlikely to break the bank, I doubt they'd move him.
Different cir stances/players, but the Pistons supposedly couldn't get an asset for Drummond (other than cap space) and the Cavaliers can't get one for Love, so it's unlikely Aldridge fetches multiple ones.
Also, the Spurs are an easy mark, who'll likely be more concerned with "doing right by" Aldridge than maximizing value.