No. 5: Josh Hader
Josh Hader hasn't thrown a pitch for the Astros yet and he's already one of the biggest signings in franchise history. He's arguably the best closer of his generation, with career marks of a 2.50 ERA, 0.94 WHIP, 165 saves, and an almost unfathomable 15.0 SO/9.
He was the top reliever on the market in 2023, and was never seriously linked to Houston for much of the free agent period, and for good reason. The Astros simply don't spend on top free agents and they don't give out long-term contracts. A top free agent, of course, is looking for high dollars and contract security.
That the Astros gave Hader both of these things is massive. He's one of the filthiest arms in the game, and beyond that, teams about to enter a rebuild don't hand out contracts like the Astros just gave Hader.
For all of the chatter about the title window getting ready to close after 2024, is the Hader signing emblematic of the Astros turning a page and deciding to begin opening the checkbook with more regularity? It's entirely likely we look back on the signing of Hader as a sign of things changing with how the front office operates.