Among the numerous obstacles: Detroit has been reluctant to eat a substantial amount of money in a deal for the ace, at least without receiving premium prospects in return. And the extent of Verlander's interest in waiving his no-trade clause for a move to Houston is unknown.
But the Collective Bargaining Agreement offers several solutions -- if the Astros, Tigers and Verlander are sufficiently motivated.
If Verlander is unsure about staying in Houston until his contract expires in 2019, he could insist on adding an opt-out clause to the contract following this season -- or '18 -- as a condition of waiving the no-trade protection.
The CBA's language allows Verlander to do so -- as has been the case under previous versions of the basic agreement, according to sources with close knowledge of the document. The MLB Players Association would support such a request, because opt-out clauses are seen as increasing a contract's value -- even though activating an opt-out would involve Verlander forgoing $28 million in guaranteed salary in 2018 and/or '19.
The presence of an opt-out clause could dramatically shift the calculation of fair market value by the Astros and Tigers. The Astros wouldn't want to surrender premium prospects if Verlander intends to depart after the season; similarly, Houston likely would be uneasy with the risk of an injured or ineffective Verlander deciding not to opt out.
Yet, the CBA offers the Astros and Tigers some flexibility here, too. Detroit can include cash to offset Houston's financial risk in the deal, and that amount can be conditional, pending the exercise of an option, according to one source.
And in this context, MLB officials consider opt-out clauses to be player options.
For example, the Tigers could include $10 million payments for the 2018 and '19 seasons as part of the deal -- and stipulate that they'd be paid only if Verlander declined his opt-out clause, should one be created.
So the Astros would have a degree of financial protection from injury or underperformance, the apparently retooling Tigers would guarantee at least some future payroll savings and Verlander could chase an elusive World Series ring with the American League's best team, without immediately committing long-term to a new city.
Does that guarantee a trade will happen? Hardly. But it shows that the parties have unique tools with which to find common ground, at a time when the Astros may not have the luxury of waiting for a perfect solution: Houston has a 5.35 ERA since the All-Star break, the worst mark in the AL.
Verlander -- who cleared trade waivers earlier this month, according to the Detroit Free Press -- is among the best available options to help boost the Astros' rotation. Including a dominant outing Wednesday against the Pirates, in which he allowed one hit over eight scoreless innings, Verlander has a 1.91 ERA over his past seven starts.
Jon Paul Morosi is a national columnist for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.