ATLANTA -- Mets closer Frank Francisco suffered a setback in his rehab assignment and will be shut down for a day before he is reevaluated Sunday, manager Terry Collins said.

Francisco is on the 15-day disabled list with a left oblique strain. Collins said Francisco's oblique "just didn't feel right."

"He's so big and strong, if he's not ready to go out there, he can do some serious, serious damage to it," Collins said.

Left fielder Jason Bay, however, is progressing toward a return from the seven-day DL. Bay played in a rehab game Thursday in high Class A Port St. Lucie, and Collins said he will play a rehab game in Triple-A Buffalo soon. Collins plans to check with Bay this weekend about his progress.

"I told him when he left, I'm going to call him this weekend, and be honest with how he's swinging," Collins said. "When he feels like he's swinging as well as he can swing, he's coming back."

As second half begins, Mets face tough tests

ATLANTA -- The Mets began the second half in third place in the National League East and play six straight games against the two teams ahead of them in the standings -- the Braves and the Nationals. Manager Terry Collins said he doesn't view the next six games any differently, despite the chance to make up ground.

The rest of July, however, Collins said will be crucial to determining the success of the rest of the season.

"We're going to know our standing when we get to Aug. 1, if we're still in the dogfight," Collins said.

In the next 2 1/2 weeks, the Mets play six games against the Nationals, host the NL West-leading Dodgers and begin an 11-game West Coast road trip.

While Collins can wait until August to determine whether he feels like the Mets can contend for the rest of 2012, general manager Sandy Alderson doesn't have that luxury. With the non-waiver Trade Deadline approaching on July 31, he must decide whether to be a buyer or seller in the trade market.

Collins, however, said the Mets can't try to make Alderson's decision for him.

"We've got to show to ourselves and the guys in that room that we're good enough and that we can compete right now," Collins said. "Because if you don't make a move, they better still believe they're good enough."

Edgin impresses Collins in Major League debut

ATLANTA -- Before Friday's game, manager Terry Collins said he was willing to throw left-hander Josh Edgin right into the fire.

"That's why he's here," Collins said. "Guess what? It's the middle of July. It's fire time."

And so, a few hours later, Edgin got a trial by fire.

On the day he was called up from Triple-A Buffalo, Edgin made his Major League debut. When he entered the game, which was eventually won by the Braves 7-5, the Mets trailed by one run in the fifth inning. There was one out and the bases were loaded with Braves.

The first hitter Edgin faced was pinch-hitter Juan Francisco. After falling behind 2-0 to Francisco, Edgin came back to strike out him and All-Star center fielder Michael Bourn to end the inning.

"I had the jitterbugs; I had to get over them," Edgin said. "The team's in a position to win, [and I] got through that inning and stayed there."

Collins stuck with Edgin to start the sixth and he retired Martin Prado and Jason Heyward. But facing Chipper Jones, Edgin hung a slider that Jones hit into the center-field seats for his seventh home run this season.

Edgin gave up a double to Freddie Freeman and was then removed by Collins. Freeman came around to score, sullying what had been a good Major League debut.

"Bases-loaded jam, I commanded my pitches," Edgin said. "Next inning, not so much. You can draw the line right down the middle there."

Collins said he liked what he saw from Edgin.

"Very impressive, tough situation for him to come into," Collins said. "I was very impressed. He threw the ball great."