Espinosa, who has been solid in place of the injured Anthony Rendon at second base, left Saturday's game in the eighth inning with what turned out to be cramps in the steamy weather.
"I drink a lot of fluids, but for whatever reason yesterday, it got me," said Espinosa, who started Sunday's game against the Dodgers. "I was cramping in the sixth inning. I got a base hit as I was going down the line, (I felt) tight.
Espinosa planned to take a couple of IV's before the game to make sure he was especially hydrated.
Rendon, who has played in just 18 games, the last one on June 24, because of knee, oblique and quadriceps injuries, isn't sure when he'll return.
"You always got to keep the faith," said Rendon, who played three innings Saturday night on a rehab assignment at Class-A Potomac . "When you go through your bad times, that's when you get tested and that's how you learn."
Center fielder Denard Span, sidelined since July 6 with a back injury, had cortisone injections on Monday to try to relieve the pain that he believes has its roots in a rapid return from a sports hernia surgery in December followed by an abdominal operation three months later.
"I feel better," said Span, who began his physical activity by jogging on a treadmill and playing catch late last week. "(But) I haven't swung a bat so it's kind of hard to tell where I'm at."