He fills the void created when Oliver Perez was pulled from the rotation and subsequently placed on the disabled list with right knee tendinitis. Whether Niese gets a second start the next time through the rotation, Wednesday against the Braves, probably will be contingent upon his performance against the Pirates.
Pirates pitchers, meanwhile, have allowed a homer in 10 of the last 11 games, with opponents totaling 14 in that span.
Jeff Karstens(notes) (1-1, 5.85), who's 0-1 with an 8.10 ERA in his last two outings, will take the mound Friday. The right-hander gave up five runs and six hits in five innings as Pittsburgh lost 5-0 to Cincinnati on Sunday.
Karstens' first start against the Mets came Aug. 17, when he suffered a 4-0 defeat after allowing four runs and nine hits in six innings.
Tim Redding is nearing a return from the disabled list and could assume a role as a starter or a long reliever. Redding had a six-inning rehab start with Buffalo on Wednesday, during which he limited Lehigh Valley to one run.
"I think we're in a situation where we can now evaluate that spot on a turn-by-turn basis," manager Jerry Manuel said. "This will be a good opportunity for (Niese). But if he's not quite ready, Redding or another starter down there could take that place."
Niese made three September starts for the Mets last season and had a 7.07 ERA. His finest performance came when he tossed eight scoreless innings against the Braves on Sept. 13 to earn his lone major league win.
METS 7, PHILLIES 5: Carlos Beltran and David Wright had two-run homers off Jamie Moyer in the first inning, and Jose Reyes added a solo shot an inning later. Mike Pelfrey improved to 4-0 by limiting the Phillies to three runs in seven innings. Francisco Rodriguez picked up his fourth save in four nights and is 9-for-9 in save chances this season.
--Manager Jerry Manuel was ejected Thursday for the first time this season. Manuel was objecting to obstruction called on SS Jose Reyes during a rundown involving Shane Victorino in the eighth inning.
--CF Carlos Beltran had 57 career at-bats against Jamie Moyer without a homer before a first-inning homer off the 46-year-old southpaw Thursday. Esteban Loaiza now becomes the pitcher against whom Beltran has the most career at-bats without a homer (39), followed by Mark Mulder and Barry Zito (38 apiece).
--LHP Johan Santana's 0.91 ERA is the third lowest in franchise history through the first six starts of the season. David Cone had a 0.76 ERA in 1988, and Nolan Ryan had a 0.77 ERA in 1971.
--OF Jeremy Reed, who was obtained from the Mariners last offseason with J.J. Putz and Sean Green, started Wednesday for the first time as a Met. He went 0-for-2. Reed, typically a defensive replacement, had his projected playing time greatly reduced once the Mets signed Gary Sheffield on the eve of the season.
BY THE NUMBERS: 11 -- Scoreless innings tossed by RHP Brian Stokes this season, entering a May 4-5 series in Atlanta.
QUOTE TO NOTE: "We have good guys, solid professionals. There is a smile on David Wright's face, a smile on Jose Reyes' face. But there is not an edge to them. Some people see edge as leadership. Sometimes, you need a little meanness to your game. Some people perceive leadership as meanness. I couldn't tell you that we have that type of guy. We have leaders. But everyone's perception of leadership is different." -- GM Omar Minaya, to Fox's Ken Rosenthal. Minaya subsequently backed away from that assessment after recognizing the comments were inflammatory.
--SS Jose Reyes had six consecutive hitless games against the Phillies, during which he was 0-for-26, before snapping that drought with a second-inning homer Thursday against Philadelphia's Jamie Moyer. The slumping Reyes entered the game with a .248 season average, 37 points below his career average.
--LHP Johan Santana, who tossed seven scoreless innings Wednesday against the Phillies, has allowed two earned runs or fewer in 12 consecutive starts. That's the fourth-longest streak of allowing two earned runs or fewer in franchise history, behind Dwight Gooden's 15-game stretch in 1985-86 and a pair of 13-game streaks by Tom Seaver, in 1971 and 1973.
RHP Tim Redding (weak right shoulder) went on the 15-day disabled list retroactive to March 27. He faced hitters in extended spring training on April 25. His made a rehab start for Class AAA Buffalo on May 6. It was uncertain whether he'd make another rehab start before being activated.
C Brian Schneider (strained back) went on the 15-day disabled list retroactive to April 16. He had a setback due to a calf injury in early May, and he will not resume playing in extended spring training before May 11.
OF Angel Pagan (arthroscopic right elbow surgery in March 2009) went on the 15-day disabled list retroactive to March 27. He will be out until at least late April.
LHP Billy Wagner (Tommy John surgery in September 2008) went on the 15-day disabled list retroactive to March 27. He will attempt to throw at the Mets' spring training complex in April, and he hopes to return for the final month of the season.