Alex Reyes picked up his 24th save in 25 opportunities.
DeJong connected off Bryan Shaw (3-5). St. Louis tacked on an insurance run in the ninth when reliever Phil Maton walked Dylan Carlson with the bases loaded.
Bader has multiple hits in six of the last eight games and is batting .384 (28 for 73) since returning from a fractured rib on July 1.
Ramírez put Cleveland ahead 2-1 in the fourth with his 21st homer. The Indians have lost 16 of 23 to sink into seventh place in the AL wild-card race, possibly making them a seller heading into the trade deadline Friday.
Cal Quantrill matched his season high with six innings for Cleveland, allowing four hits, including Bader’s homer. The right-hander has not lost in nine starts since June 6.
Wainwright and 10-time All-Star Molina made their 293rd start as battery-mates, which ranks fourth all-time. Molina went 0 for 4 after a three-game absence with a stiff neck.
Indians manager Terry Francona returned to the dugout after missing the previous two games with a head cold. Francona is six wins away from tying Hall of Famer Lou Boudreau’s franchise record of 728 victories.
Cardinals manager Mike Shildt will employ a four-man rotation in the short term, taking advantage of three off-days in an eight-day span. RHP Johan Oviedo was optioned to Triple-A Memphis, but is likely to return to St. Louis when eligible on Aug. 5.
RHP Jack Flaherty, who has been on the injured list since June 1 with an oblique strain, struck out three over two scoreless innings Tuesday for Memphis and could be activated in mid-August.
Cardinals: RHP Miles Mikolas (right forearm tightness) will make his second rehab start for Triple-A Memphis on Thursday. Mikolas retired all nine batters he faced on 29 pitches Saturday at Louisville.
Indians: RHP Cam Hill (right wrist surgery), who is on an extended rehab assignment with Triple-A Columbus, has allowed six runs and recorded three total outs over his last two appearances.
Cardinals: LHP Kwang Hyun Kim (6-5, 2.88 ERA) has won five straight starts, limiting opponents to a .155 batting average with a 0.90 ERA over 30 innings.