Philadelphia makes gut call and hopes that home/road splits and DER marks will not matter as Blanton moves from pitcher-friendly McAfee Coliseum to the bandbox of Citizens Bank Park.

While the Mets extended their winning streak to 10 games which forced a tie for the National League East lead Thursday night, the Phillies put the finishing touches on a deal to bolster their starting rotation, sending three minor leaguers to the A’s for Joe Blanton.

Starting pitching was one area where New York held an edge over Philadelphia and the Phillies hope Blanton can slot in after Cole Hamels and Jamie Moyer. What can the club hope to get from Blanton?

In 2007, Blanton was second in the American League with 230 innings pitched. He finished 14-10 for the year, giving him 30 wins the past two seasons. Blanton is not overpowering but he rarely walks anyone and he does a good job keeping the ball in the park, as he has allowed 0.82 HR/9 IP in his major league career.

But Blanton has been helped by a solid Oakland defensive team in general and McAfee Coliseum in particular the past three seasons. In 2008, the A’s lead the majors in Defensive Efficiency, which measures the rate at which balls in play are converted into outs, with a 0.724 score. Also this year, the A’s home park has cut offense by 11 percent compared to an average stadium, while McAfee’s three-year park factor is 93, with 100 being an average score.

How has that impacted Blanton? For his career, Blanton’s ERA is virtually a full run greater on the road (4.78) compared to McAfee (3.79). Last year he had a 5.11 ERA on the road and a 2.69 mark at home. This year his road ERA stands at 5.73 with 24 earned runs in 37.2 innings pitched.

Meanwhile, Citizen Bank Park, Blanton’s new home field, has a three-year park factor of 104. Last year Phillies pitchers gave up 125 home runs at home and only 73 on the road. Will Blanton’s ability to keep the ball in the park help neutralize the affects of home-run crazy Citizen Bank Park or will his new home field destroy one of the main assets Blanton brings to the table?

With top starting pitchers C.C. Sabathia and Rich Harden already off the market, the Phillies’ hopes of landing a stud pitcher were dwindling. The other top hurlers rumored to be available came with serious question marks, too. A.J. Burnett alternates outstanding performances with beatings while Erik Bedard is a huge injury risk.

Philadelphia is second in the National League with an average of 5.01 runs per game, so if Blanton can keep the score close he has a good chance of emerging with a win.

But it is hard to imagine Blanton’s other stats improving with his move to Philadelphia. Both his ERA and WHIP could take a serious hit moving from McAfee to Citizens Bank and they were nothing special to begin with this year.

It was a gamble the Phillies had to take. Adam Eaton and Brett Myers have been dismal in the rotation while Kyle Kendrick and Jamie Moyer are nobody’s idea of top of the rotation starters.

The best prospect Philadelphia gave up in the deal, Adrian Cardenas, is a second baseman blocked by Chase Utley. Blanton is on a reasonable one-year contract and is eligible for arbitration and not free agency.

But it is unlikely this deal will benefit either Blanton or the Phillies in the short-run. Blanton has been a below-average pitcher this year, even in pitcher-friendly McAfee. His ERA+ (which adjusts for home park) of 77 fits in nicely between Myers (76) and Eaton (78), the two pitchers from which Philadelphia was looking to upgrade.