Instead the Cardinals are likely to use the opportunity to give Matt Holliday a breather from left-field duties while still keeping his bat in the lineup.
The Cardinals can then plug in either Peter Bourjos or Shane Robinson as the extra position player. That would also improve the club defensively.
"The first [thing you do] is maybe figure out how to get our guys a little bit of rest," Matheny said of having the DH. "We have a couple of outfielders who are capable of going out there and doing a great job for us, and still being able to keep Holliday's bat in the lineup is certainly going to be a consideration."
Shortstop Jhonny Peralta and first baseman Matt Adams would be other candidates to serve as DH.
The rest of the Cardinals' Interleague road contests came during an eight-game span in June, and because they were played consecutively, it allowed the Cardinals to structure their roster to handle the addition of the DH. Making such a move for just three days, though, would be more complicated.
Outfielder Randal Grichuk, who hit his 21st Triple-A homer on Tuesday, would have been the likely candidate had the Cardinals wanted to dip into their system for an extra bat.
Jenifer Langosch is a reporter for MLB.com. Read her blog, By Gosh, It's Langosch, and follow her on Twitter @LangoschMLB. Teddy Cahill is a reporter for MLB.com. Follow him on Twitter at @tedcahill. This story was not subject to the approval of Major League Baseball or its clubs.