"We're going to deal with the next three days, when we already have scheduled starters," Porter said. "It's an ongoing conversation with myself, [pitching coach] Doug Brocail and [general manager] Jeff [Luhnow]. When we come out of the off-day Thursday, we're going to reset the rotation moving forward from there."
That off-day means Peacock's next outing likely wouldn't be for another week if he gets the starting nod.
Brett Oberholtzer is getting his chance in the rotation after locking down the Orioles last week, leaving only lefty Dallas Keuchel's spot potentially up for grabs with Jordan Lyles, Erik Bedard and Jarred Cosart entrenched as starters after Bud Norris was traded to Baltimore.
In two stints with Houston earlier this year, Peacock was rough around the edges, going 1-3 with an 8.07 ERA in nine appearances (five starts). That led to a lengthy stint in Triple-A, where fastball command was the top priority.
"He was leaving a lot of fastballs up in the zone when he was here," Porter said. "Yesterday, he not only pounded the zone from a strike standpoint, but he pounded the bottom of the zone. When you have his kind of velocity, it makes his breaking stuff that much better, especially down near the knees.
"He did a good job working on his slider, and it complements the breaking ball he has. You then get a tough combination of the curve and slider and mix that in with the changeup, so he can be great."
Chris Abshire is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.