"He's swinging better, and I want to keep him that way," Melvin said. "I want him to stay on that, and sometimes a particular lefty can give you some trouble and get your bat going in the wrong direction."
Reddick entered the day 0-for-3 with a strikeout against Lester and as one of just four hitters on the A's roster who has even faced him before. Casper Wells is another, but he, too, sat on the bench for the matinee -- and mostly for reasons other than his 0-for-10 career showing against the southpaw.
Reddick made a pinch-hitting appearance in the eighth inning, but he struck out against Koji Uehara.
There was thought that Wells, acquired by the A's on Monday, would make his first start in green and gold on Wednesday with a lefty going, but "I want to let him run around on the field here today," Melvin explained.
"He didn't even get batting practice yesterday. He's in the game late last night and he sees one pitch. We'll let him get a little bit comfortable out on the field with us before we get him in a game."
It's likely Melvin finds a spot for Wells in the lineup come Friday, when Orioles lefty Wei-Yin Chen is scheduled to start in Oakland. But two days later, it's possible that Wells is bumped from the roster, with Yoenis Cespedes expected back from the disabled list.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.