Melvin said Weeks' move back to the top had more to do with Josh Reddick getting the day off than any permanent change in lineup construction.
Weeks had made 87 starts hitting first or second before sliding down to ninth this week, where Melvin said he likes to have him.
"I think he's doing well down there," Melvin said. "So it might just be today's lineup. It might not."
Melvin said there was a good chance Jonny Gomes will claim the No. 2 spot in the order against left-handed starter Wei-Yin Chen on Sunday.
Gomes started in the two-hole in each of the A's five matchups with lefties this week before getting the day off against right-hander Tommy Hunter on Saturday.
"That's worked pretty well for us," Melvin said. "We're not afraid to mix it up. You try to have some stability within the lineup. I think we've had some stability recently with lineups against lefties."
Gomes is hitting .440 since the All-Star break, a shift he credited to playing multiple days in a row rather than anything having to do with his spot in the order.
Neither Gomes nor Weeks said their spot in the order affects their approach, but the two options clearly have different impacts on the offense.
While Gomes owns the better on-base percentage, Weeks is a threat with his speed, as evidenced by his 13 steals.