Obviously there are plenty of additional factors that go into a trade - contracts, age, speed, chemistry, etc. But just from a basic statistical standpoint, take a look at these four players:
Player 1: .238/.302/.373, 11 HR and 62 RBI, 92 OPS+, Below-average defender
Player 2: .262/.353/.510, 20 HR and 62 RBI, 133 OPS+, Poor defender
Player 3: .227/.307/..395, 15 HR and 53 RBI, 101 OPS+, Average defender
Player 4: .247/.290/.423, 14 HR and 54 RBI, 95 OPS+, Below-average defender
Think about which one(s) you'd like the Phillies to trade for and which ones you wouldn't want on your team. Do you think, just based purely on their stats and a brief defensive evaluation, that any of these guys would help the Phillies get closer to the World Series than they are now? Do you think any of them is much better than Raul Ibanez or Domonic Brown? Do you think any of these guys is worth trading a high-level prospect for?
(I'll reveal who the four players are in the comments section)