NEW YORK -- Finally, there's light at the end of the tunnel.

Injured center fielder Carlos Beltran said he is certain he will play on Tuesday, despite not feeling sharp as late as Sunday morning.

"[On] Tuesday, I'm going to be able to be in the lineup, for sure," Beltran said. "[Monday]'s a day off, so it's going to be better for me."

Beltran said he felt about 70 percent on Sunday morning, three days after bruising his right knee in a collision with Giants first baseman Rich Aurilia. He was still walking with a slight limp, but has been taking anti-inflammatories to reduce the pain.

"When I run, I feel kind of a little bit of pain, but I believe it isn't going to get worse," Beltran said. "It isn't going to get better in two days, [not to] 100 percent, but if I can get to 80-85 percent, that's good for me."

Beltran had been batting .297 with eight home runs before the injury.

Decisions looming: With Beltran set to return on Tuesday and outfielder Moises Alou also hoping to play at some point during this week's Philadelphia series, the Mets should find plenty of relief coming their way.

But those returns also bring with them a new dilemma: Who, exactly, should be sent back down to Triple-A?

Beltran's return won't affect any of his 24 teammates, as the center fielder was never put on the disabled list. But Alou was, and so, too, was second baseman Jose Valentin, due back within the next week to 10 days. When that duo gets healthy, two current Mets will have their tickets punched back to New Orleans.

The leading candidate remains Carlos Gomez, whose blistering speed hasn't made up for his empty bat. Gomez's pinch-hit single on Saturday snapped an 0-for-18 skid, but that worked only to raise his average to .194.

"They're going to probably try to exploit his weaknesses," said Mets manager Willie Randolph. "He needs to do what he did last night, which is just shorten up his stroke a little bit and put the ball in play. He's 21 years old, and he's going to go through his ups and downs as a hitter."

Assuming Gomez goes down when Alou returns, there's still no certainty of who will make room for Valentin. Logic says it would be Ruben Gotay, the infielder who first came to Shea when Valentin got hurt.

But Gotay has been hot, providing big hits, like Saturday's three-run homer, for the Mets. Because of that, the team may be willing to carry four middle infielders, likely opting instead to demote the recently promoted Ben Johnson.

"He's shown that he wants to be a part of things," Randolph said of Gotay. "When we get down to the other guys coming back, we'll look at that. He's proven he can play up here."

Pedro primed: Pedro Martinez is set to throw off a mound for the first time on Tuesday, at the Mets Minor League complex in Port St. Lucie, Fla. That keeps him on schedule to return sometime in August.

"Everything with Pedro is all positive," Randolph said. "[It's] all good stuff I'm hearing about him."

Power outage: Although the first genuine HHH -- hazy, hot and humid -- stretch of the summer has yet to assault us, New York already has endured a brown-out -- in Queens, mostly. The Mets power has been cut.

The home runs Carlos Delgado and Ruben Gotay hit on Saturday in the Mets' 7-1 victory against the Diamondbacks were the team's 27th and 28th at Shea Stadium this season. At the rate the Mets have established thus far this season, they will hit just 78 home runs at home this year, 18 fewer than they hit in 2006.

Through 29 home games last season, the Mets had hit 38 home runs at Shea, including 13 combined by Delgado and David Wright. The two have combined for 16 home and away this season. The cold April seemingly wasn't an issue, because opposing teams hit home runs. Indeed, opponents had hit 36 at Shea through Saturday. Last year, the Mets allowed 82 home runs at Shea, 14 fewer than they hit.

Not that the power-down has affected the Mets' run production that much. They tallied 132 runs in their first 29 home games last year, and in their first 29 home games this season, the Mets scored 135 runs.

This date in Mets history -- June 4: The Mets scored an unearned run in the 15th inning to beat the Dodgers, 1-0, at Shea Stadium on this date in 1969. The Miracle Mets had a 9-5 record in 1-0 games. ... Jerry Koosman allowed five hits in a 1-0 victory against the Astros at Shea on June 4, 1975. The Mets split their two 1-0 games in '75. ... One day after he had gone berserk in the clubhouse following an 0-for-5 performance in which he left seven runners on base in a 2-1 home lose to the Cubs, Dave Kingman hit three home runs and drove in a club-record -- still standing -- eight runs in Los Angeles on this date in 1976. The Mets beat the Dodgers, 11-0, on a three-hitter by Tom Seaver.

A home run by Steve Yeager against Neil Allen in the seventh inning provided the decisive run in a 2-1 Mets loss to the Dodgers in LA on this date in 1983. The loss, Allen's seventh in nine decisions, moved the Mets closer to trading their closer. Eleven days later, Allen and Rick Ownbey were dealt to the Cardinals for Keith Hernandez.

After Dwight Gooden escaped bases-loaded, none-out jeopardy in the eighth inning, the Mets scored three times in the top of the ninth to beat Fernando Valenzuela and the Dodgers, 4-1, on June 4, 1985. The rally included Gooden's third single of the night. ... On this date in 1991, Hubie Brooks separated manager Bud Harrelson and David Cone, that night's pitcher, during a heated argument in the visitors' dugout in Riverfront Stadium in Cincinnati. ... The eventual National League champion Mets were pounded, 15-5, by the Devil Rays on this date in 2000, one day after Al Leiter and three relievers beat the Rays in a 1-0 Mets victory.

Coming up: After an off-day on Monday, the Mets face their division rivals the Philadelphia Phillies in a three-game set. On Tuesday, Tom Glavine and Jamie Moyer reprise their confrontation of April 12, won by Glavine and lost by Moyer, in a 7:10 p.m. ET game at Shea Stadium.