PHILADELPHIA -- Mets manager Willie Randolph will have to do some serious juggling with his rotation after Jorge Sosa was placed on the disabled list on Sunday.

An MRI determined that Sosa suffered a Grade 2 strained left hamstring on Saturday, which is considered a moderate injury, with Grade 4 being the worst. Sosa was replaced by right-handed pitcher Mike Pelfrey, who was called up from Triple-A and started for the Mets on Sunday in the series finale.

Meanwhile, Oliver Perez will not start for the Mets on Tuesday. Perez was scheduled to start on Sunday, but he has been experiencing a slightly strained lower back following his last start.

Perez said that he felt better after a stretching session prior to Sunday's game, but it wasn't good enough for him to start.

"It's better, but not good enough to pitch," said Perez, who will miss his next two starts.

Both sides now: When Carlos Beltran hit home runs from both sides of the plate in Saturday's 8-3 victory over the Phillies, he extended a somewhat arcane, but nonetheless, surprising Mets record.

A Mets player has hit "switch" home runs in a game 17 times. No other National League franchise has achieved that feat as often. The Yankees have the most in Major League history with 35. The surprising element is that the Mets were born in 1962, and their first instance of "switch" homers didn't happen until 1979, when six NL franchises were at least 90 years old.

Lee Mazzilli was the first Met to hit "switch" home runs in the same game on, Sept. 3, 1979. The second instance didn't happen until 1991, when Howard Johnson accomplished the feat. Then, beginning in 1993, Bobby Bonilla (four times) and Todd Hundley (five times) did it nine times in five seasons. Beltran and Jose Reyes (twice each), Tony Clark and Carl Everett are responsible for the others. Beltran has done it five times in his career.

The Major League record, 11 times, is shared by Chili Davis and Eddie Murray. In August 1964, Mantle had hit "switch" home runs 10 times.

"Right now, I'm having a great time," said Beltran, who socked his 13th and 14th homers of the season, and saw his average jump from .268 to .277 with his 4-for-5 day. "I think this comes from working in the cage. It takes days to carry that into games. But I feel good mechanically, staying inside and using my hands more."

That wasn't always the case. Early this season, Beltran admitted that he felt he needed to adjust on the left side of the plate. He entered Saturday's game hitting .290 from the right side and .258 from the left side.

"I felt good from the right side since the start of the season, but I wasn't feeling the same way from the left side of the plate mechanically," Beltran said. "I felt too tall, reaching for the ball, not seeing the ball out of pitcher's hand. I was struggling, thinking too much. I think it's OK now."

Beltran's four hits tied a career best, and it marked the 19th time in his career he had a four-hit game.

"He's been a big boost, and I hope it's one of those streaks he keeps up into the [All-Star] break," Randolph said about Beltran. "He'll tell you that it's no secret that he's seeing the ball well, and he's hitting it."

The other Pedro producing: Pedro Feliciano posted his first career save in Saturday's victory. The southpaw has been particularly hard on lefties, doing a very good job retiring the Phillies' two big guns, Chase Utley (by strikeout) and Ryan Howard (flied out to center).

"My job is to pitch in the eighth inning and get guys out, lefties and righties," Feliciano said. "Billy Wagner and Scott Schoeneweis have been a big help, especially about facing left-handed batters. I get great satisfaction over what I'm doing. And I feel confident, but I have to watch from getting too overconfident.

"Everything is working -- my sinker, slider, changeup. When I throw the slider hard or slow, especially the front-door slider, it works, because hitters like Utley and Howard are looking fastball. And right now, I feel good. I thought I'd be a little sore [on Saturday] after going Friday, but I am a little sore today. But I can go if they need me."

A gray area: The difference between the performances of Schoeneweis at Shea Stadium and elsewhere is a contrast of black and white. His ERA in 21 appearances at Shea is 9.53. After pitching a scoreless inning on Saturday, his ERA in 14 appearances on the road is 0.00.

Said Schoeneweis on Saturday: "Maybe I should start wearing the road grays [uniforms] under my whites at home."

This date in Mets history July 2: In a game that had no extra-base hits and one RBI, the Mets defeated the Cubs, 2-1, behind Jerry Koosman's three-hitter at Shea on this date in 1976. ... Four years later, Brooklyn-born John Pacella, who made his big-league debut with the Mets on his 21st birthday in 1977, pitched 7 1/3 innings in the Mets' 3-1 victory against the Cubs at Shea. He was the winning pitcher, Mazzilli hit a home run and the winning manager was Brooklyn-born Joe Torre.

Terry Leach pitched a two-hitter in the Mets' 5-0 victory against the Reds at Riverfront Stadium on this date in 1987, putting his record at 7-0. It was the third and final complete game in his 21 big-league starts. All three were shutouts, a 10-inning one-hitter against the Phillies, a two-hitter against the Reds and a three-hitter against the Giants.

The Mets lost to the Tigers in old Tiger Stadium, 9-7, on this date in 1997. The loss completed a three-game sweep in which the Tigers hit 14 home runs, three by Damion Easley and none for the Mets.

Coming up: The Mets make their lone 2007 visit to Denver, starting on Monday. Tom Glavine will go for his 298th victory of his career at Coors Field, where he has pitched two shutouts. No other pitcher, not even a member of the Rockies, has more than one. Jason Hirsh will start for the Rockies in the 9:05 p.m. ET game.