SAN DIEGO -- Already a key piece of New York's bullpen, rookie left-hander Josh Edgin is about to see his role increase once more.

With Tim Byrdak landing on the disabled list Friday with a sore left shoulder, Edgin is now the sole lefty in Terry Collins' bullpen. That means that whenever possible, Collins will wait to use Edgin until the later innings, trying to match him up against an opposing team's most daunting left-handed slugger.

"We're going to pick our spots, not rush him into the game," Collins said. "We'll probably save him until that seventh, eighth inning, depending on what the matchups are going to be."

Edgin's expanded role has not come without merit. Since struggling through his first few Major League outings, the 30th-round pick has been nearly unhittable. He has not allowed a run over his last eight appearances, striking out 12 batters and walking two in 7 1/3 innings entering Saturday.

Should the Mets face a sticky situation against a left-hander earlier in a game, Ramon Ramirez -- a right-handed pitcher with strong career splits against lefties -- will likely receive the ball. Like Edgin, Ramirez has been strong of late, holding opposing hitters to an .067 average over his last five outings.

"That's certainly why we got him," Collins said. "He's been throwing the ball much better lately, so I think that's where you're going to see more of Ramon in those spots."

Baxter walks into Mets history

SAN DIEGO -- Apparently Mike Baxter, a former Padres outfielder, has earned quite a reputation in San Diego.

The Padres pitched inside to Baxter in Saturday's game. They pitched outside. They pitched up and they pitched down. In short, they threw the ball everywhere but over the plate, allowing Baxter to set a nine-inning Mets record and tie a National League mark with five walks in five plate appearances.

"It's just strange," Baxter said. "It's funny because it's the only thing that happened tonight. But I'll take it."

No Mets player had walked five times since Vince Coleman in 1992, and he needed a 16-inning game to do it. No Major Leaguer had walked five times in a nine-inning game since Mark Teixeira pulled the trick in 2009.

But sitting on four walks in the eighth inning of Saturday's 6-2 win, Baxter jumped out to a 2-0 count, took a strike, then watched two more balls for the record-setting free pass.

Of the 25 pitches Baxter saw in the game, only five were strikes. Thirteen of the final 14 pitches he saw were balls, several of them not particularly close.

"Each at-bat, it's not like I was looking to walk," Baxter said. "I'm still trying to hit and trying to drive guys in. I just ended up walking."

A fourth-round Draft pick of the Padres in 2005, Baxter appeared in nine games for them in 2010 before hooking on with the Mets last season. In eight plate appearances with San Diego, he did not draw a walk.

Harvey's Citi Field debut set for Friday

SAN DIEGO -- For all Matt Harvey has accomplished in his first week-plus in the big leagues, Mets fans have not yet had an opportunity to watch the rookie pitch in New York.

That will change Friday, with the Mets planning to slot Harvey into their series opener against the Braves at Citi Field. Previously unsure if they would use Harvey on Friday or some other date, the Mets have finally made a decision; following his third career start Sunday in San Diego, Harvey will pitch on regular rest in New York.

Much of the decision revolved not around Harvey but injured left-hander Johan Santana, who is scheduled to return to active duty next Saturday against the Braves. That gave the Mets two choices: either start Harvey on regular rest Friday, or on six days' rest the following Sunday.

Not wanting to disturb the rookie's schedule in any way, the team chose the former route. So Harvey will pitch Friday and Santana next Saturday, with Jeremy Hefner dropping out of the rotation following Saturday's start in San Diego.

"We'll fit him in there," manager Terry Collins said of Santana. "We might have to back up somebody in the next four or five days to see how we get through it, see where it all fits. Hopefully we don't have to use a sixth man, but if we need to give somebody a blow, we will."

For now, the Mets will also avoid using knuckleballer R.A. Dickey on three days' rest, though that could change when the team plays 13 consecutive games without an off-day later this month. Using Dickey on short rest ideally would allow the team to give Santana, Chris Young and Jon Niese extra days to recover from their starts, while keeping Harvey on schedule as often as possible.

Worth noting

• Closer Frank Francisco threw two pitches Saturday, inducing a game-ending double play for the save. It was Francisco's first appearance since a five-week stay on the disabled list. Though Collins said pregame that Francisco would appear in Saturday's game no matter what, he changed his tune afterward, saying he did not want to risk aggravating Francisco's sore right lat in a non-save situation, which became moot after the Padres homered and put two runners on against Bobby Parnell.

• Triple-A Buffalo manager Wally Backman was suspended three games following an on-field confrontation Friday with Syracuse manager Tony Beasley, which resulted in his ejection from the game. Backman told the Buffalo News that he believed several Syracuse players were stealing signs from his catcher.

• Collins insisted that Jason Bay's absence from the lineup Saturday was not the start of a trend, instead stemming from his desire to load up on lefties against Padres starter Edinson Volquez. Bay will be back in the lineup Sunday against right-hander Jason Marquis, Collins said.