Houston Astros vs St.Louis Cardinals — Mar 18, 2026 | AI Prediction & Stats

The Cardinals will match veteran right-hander Miles Mikolas against Astros ace Framber Valdez. Mikolas’ sinker/slider combo has historically kept the ball on the ground against Houston’s left-handed thunder, and he enters with a fresh arm after a skipped turn. Valdez is still the league’s premier ground-ball generator, but St. Louis’ right-heavy lineup—Goldschmidt, Arenado, Walker and red-hot prospect Saggese—has owned southpaws (.276/.345/.463) all spring. Expect a cautious first inning before St. Louis scratches out a run in the second: Donovan’s leadoff double, a productive grounder, then Edman’s safety squeeze exploits Valdez’s deep release. Houston answers in the third when Peña jumps on a first-pitch cutter and Alvarez plates him with a two-out single. The middle frames tilt to the Cards. In the fifth, Arenado rolls a two-run double down the left-field line after Walker extends the inning with a nine-pitch walk, pushing St. Louis ahead 3-1. Valdez exits after 95 pitches, handing the ball to a bullpen that has logged ten innings the previous two nights. Houston mounts its only real surge in the sixth: Tucker walks, Alvarez singles, and Bregman drives both in with a line-drive double off Mikolas’ lone mistake, trimming the deficit to 3-3. Mikolas bears down, coaxing two routine grounders to strand the go-ahead run, and the Cardinals’ rested relief corps—Helsley, Rom, Gallegos—slams the door from there. In the eighth, St. Louis delivers the decisive blow. Against righty Rafael Montero, Goldschmidt rifles a gapper for an RBI triple and trots home on Gorman’s sac fly. Gallegos records a stress-free ninth, freezing Tucker on a front-door slider to seal a 5-3 victory. Superior matchup splits, bullpen freshness, and recent head-to-head confidence give the Cardinals the edge in a tightly contested clash.