"It's been building up a little bit since late Spring Training," Weiland said. "Nothing too serious; it's stuff that I've felt before, and I want to stop it before it gets worse."
Wandy Rodriguez will instead start Friday's series opener in Cincinnati, with Lucas Harrell pitching on Saturday and Bud Norris on Sunday, with each going on four days' rest because of Thursday's off-day. The Astros are hoping to be able to slot Harrell back into the rotation on Tuesday.
Manager Brad Mills is hopeful that rest will do the trick for Weiland.
"The doctor is going to look at him, and we'll see where we're at with that," Mills said. "He's got that shoulder soreness, and with the off-day, we're able to do this and take advantage of it."
Weiland (0-3, 6.62 ERA in three starts) is coming off his best outing of the season, having held the Dodgers to six hits and three runs in seven innings on Saturday, throwing a season-high 105 pitches.
The Astros acquired Weiland from the Red Sox in a trade last December.