NEW YORK -- Masahiro Tanaka is expected to miss about a month due to low grade strains in both of his hamstrings, said Yankees general manager Brian Cashman, who believes that the club has internal options capable of filling the vacancy in the rotation.
Tanaka sustained the strains while tagging up on a sixth-inning sacrifice fly in the Yankees' 4-1 victory over the Mets in Friday's Subway Series opener at Citi Field. He limped to the dugout after scoring his first Major League run and was placed on the 10-day disabled list on Saturday.
"It's certainly unfortunate, but it creates an opportunity for others," Cashman said. "We're forced to find some other things out in some other areas with some other personnel. That's always healthy, too."
In a corresponding move, the Yankees recalled utility man Ronald Torreyes from Triple-A Scranton/Wilkes-Barre. Manager Aaron Boone said that the club is evaluating internal options to take Tanaka's place in the rotation, which is projected to come up on Friday against the Rays.
"Obviously, it's very disappointing," Tanaka said through an interpreter. "You understand that it's part of baseball and that injuries are part of it, but it is disappointing that this happened. It's something that already happened and it's not something that you can take back."

Two choices from the system who would be on regular rest to make that start are Triple-A Scranton/Wilkes-Barre right-hander David Hale and Double-A Trenton right-hander Jonathan Loaisiga, both of whom were rumored as possible promotions for a spot start at Detroit last week.
A pair of rainouts in Baltimore negated the need to promote a pitcher. Cashman also noted that right-hander Luis Cessa is scheduled to throw about 60 pitches in a Minor League rehab start for Class A Advanced Tampa on Monday, and could soon become an option for the big league club.
"We took a hit, but we feel like we're covered still," Boone said. "We're working through the different options. We have something in mind. We'll just kind of see how the next couple of days unfold and then start to put a plan in place to insert another starter."
Tanaka, 29, was 7-2 with a 4.58 ERA in 13 starts this season, his fifth in New York. His injury parallels a similar 2008 scenario involving former Yankees pitcher Chien-Ming Wang, whose career was derailed while running the bases in an Interleague game at Houston's Minute Maid Park.
"I don't think it's anything special," Tanaka said. "I've been doing this since I was a little kid. It's on me that I got hurt."
Boone said that he would be in favor of the National League adopting the designated hitter, though after spending 10 of his 13 active seasons in the NL, he admitted that his stance is a fairly recent development.
"It's something we worry about and concern ourselves with," Boone said. "We should probably be a little more ... on it as a priority throughout the year. Maybe there's things that we can incorporate that better prepare us for these types of situations, starting as early back as spring."
Tanaka's DL stint marks another hit to the rotation after the team announced on Tuesday that left-hander Jordan Montgomery needed season-ending Tommy John surgery. That projects to make the Yankees significant shoppers in the starting-pitching market prior to the July 31 non-waiver Trade Deadline.
"I think we're always open to outside help, no matter what time of year it happens to be," Cashman said. "We also have internal options we can rely on."