"He's available to pitch [Wednesday]. Potentially could," Showalter said. "It's one of many options that have been communicated with him and Max and all the guys."
If the Mets choose to start deGrom, they would forgo the opportunity to give their ace extra time to rest for one of the first two games of a potential wild-card series.
"We'll make the adjustment. I'm OK with that," Showalter said. "Just keep trying to stay organized for any pivots you have to make. There are lot of potential scenarios."
Showalter said he was fine with the possibility of playing the season finale on Thursday -- potentially a day before the wild-card series is supposed to kick off -- because it would mean the division is still at play.
"It's a good thing, right?" Showalter said. "What's the downside of that? Right, so just win. I think we would all sign up for that."
The Mets would need some good fortune if they hope to win the division. If the Mets lose or the Braves win, Atlanta will take first place in the division. But if the Marlins sweep the Braves, the Mets could win the division by sweeping the Nationals.
In deGrom's appearance on Friday, the future Hall of Famer went six innings against the Braves, allowing three runs on three home runs and five hits while striking out 11 and walking none in a 5-2 loss. The Braves went on to sweep New York in three games, taking control of the NL East in the final week of the season.
Showalter said he spoke to outfielder Starling Marte, who's unable to grip a bat or a baseball, and said the finger that landed the outfielder on the injured list is improving "little by little."
"Still got some discomfort there," Showalter said. "It's very frustrating for him."
Despite the lack of progress, Showalter would not rule out Marte for a potential wild-card series.
Showalter said that reliever Mychal Givens is available to be activated off the injured list, but the Mets have not yet made the move.