But Castillo wasn't quite as optimistic about returning to the lineup on Friday.
Pulled from Monday's game after four innings and citing back spasms that wouldn't even let him bend, Castillo was still experiencing tightness on Wednesday afternoon. Prior to receiving treatment, he told reporters he didn't know whether his injury would warrant a trip to the disabled list.
"I feel better," Castillo said, holding the right side of his back. "But I don't feel 100 percent."
The second baseman was visibly frustrated with the injury, and with good reason.
After being plagued by injuries in a disappointing 2008 campaign, Castillo committed himself to a rigorous offseason regimen. The work has paid off in the season's first month; Castillo's .370 batting average is third in the National League, and he's hit .432 with four RBIs and eight runs scored in his last 14 games.
Prior to Wednesday's game, Manuel said both Castillo and Delgado -- who has been out with right hip soreness since Monday -- would be available only in "an emergency situation."
"They're still a little sore," Manuel said. "[We're] trying to stay away from those two guys if we can and have them ready for the series coming up."
Starting Friday, the Mets will play 20 consecutive days without an off-day, and a healthy Delgado and Castillo would certainly be a boost.
Delgado, who aggravated his hip sliding into third base on a triple Sunday, has a team-leading 16 RBIs. Although he has struggled on the Mets' current homestand with a .100 average (1-for-10), Delgado does have four walks and two RBIs and is a key part of the middle of the order.
Brittany Ghiroli is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.