Can we stop using these phrases?
"[Player X] doesn't put us over the top" and "[Player X] doesn't guarantee us a playoff spot"
We've played 96 games, there's 66 to go. To this point, Albert Pujols has been worth 5.3 WAR in 411 plate appearances. If you prorate that number to 650, Albert will be worth about 8.4 WAR total, or 3.1 from here on out. Three wins. That's how much Albert Pujols helps you this season. That does neither; put you over the top or guarantee you a playoff spot. It does increase your playoff probabilities - each win is worth ~5% or so, maybe more - and thus help you towards a playoff spot, but no one player guarantees you a spot at this or any point.
Cliff Lee probably adds 1.5 WAR and Victor Martinez would add around 2. That's not even four wins and those are arguably two of the three best players available. Of course, next year they would add nearly double digit wins to the fray and that has to be considered, but in terms of trading some prospects and Scott Kazmir for playoff tickets? Not likely to happen.