NEW YORK -- The Mets have seemingly found their groove in the National League Wild Card race, having won six of their past seven games entering Sunday, but the club may be facing yet another injury-related setback. Yoenis Céspedes and Neil Walker were both held out of the starting lineup in Sunday's 5-1 loss to the Phillies after past maladies have flared up in the past few days.
"We can't afford to blow these guys out, especially with the way we are playing," Mets manager Terry Collins said.
Kelly Johnson started at second base and hit third in Walker's absence while Curtis Granderson filled in for Cespedes in left field and hit fifth.
While Collins hopes to have both back in the lineup Monday when the Mets begin a pivotal three-game series with the Marlins at Citi Field, there is concern given that both players have previously missed time with these same injuries.

Cespedes was held out of the starting lineup seven times in July because of his ailing quad before ultimately landing on the DL on Aug. 4.
"I talked to Ces [on Saturday] night as soon as the game was over," Collins said. "We took him out because he scored on the [Alejandro] De Aza double and coming around third, he could feel his quad and that was it. We can't afford to lose this guy for another 15 days. I told him, 'One day, I gotcha, and if we need to hit you, I gotcha,' but I know [Monday] night he'll be in the lineup, and that's a better feeling than knowing I don't have him."
Walker has battled lower back issues the past few years and has been forced to miss games on multiple occasions this season, most notably three games from June 12-15. The second baseman was scratched from the lineup Aug. 16 because of his back and spent the next three days on Major League Baseball's paternity leave list, but the issue has still persisted.
"Neil played right before he left San Francisco and [his back] was barking a little bit," Collins said. "We thought the rest would help, but he came back and it improved but not immensely. I talked to him [Sunday] morning and he really needs a lot of time to get loosened up and stretched back out and day games don't allow that."
Both Cespedes and Walker have been key cogs in the Mets' offense. Since returning from the DL on Aug. 19, Cespedes was hitting .355/.429/.806 with four home runs and eight RBIs. Meanwhile, Walker has wielded one of baseball's hottest bats over the past month, batting .440 (40-for-91) with seven home runs and 15 RBIs over his past 23 games.