NEW YORK, N.Y. - Sean Callahan is the newest member of the Army football team. In conjunction with the New York Yankees' HOPE Week and the Friends of Jaclyn Foundation, Callahan was adopted by the Black Knights, Wednesday at the Hard Rock Café in Times Square.

Callahan, 11, from Mahopac was presented with an Army team jersey by assistant head coach for defense and Bronx native, Orlando Mitjans, Jr., during Wednesday's festivities.

Callahan, who will have a locker with the football team, will be introduced to the football program later in the summer when the players return from summer training for the start of fall camp.

"We could not be more excited to welcome Sean," said Army head football coach Jeff Monken. "We hope to see Sean and his family often. Sean is going to get a first-hand look at Army football. We will get him in the weight room, at practice and on the sidelines. He is a tremendous young man and I know our players are going to benefit from having him around."

Introduced in 2009 and now celebrating its sixth year, the Yankees' HOPE Week initiative (Helping Others Persevere & Excel) is rooted in the belief that acts of goodwill provide hope and encouragement to more than just the recipient of the gesture.

For five consecutive days, the Yankees shined a spotlight on a different family, individual or organization. Wednesday it was Callahan's turn.

Callahan recently underwent his second stem cell transplant due to his brain tumor and was connected to the Army football through Friends of Jacyln Foundation, whose mission is to improve the quality of life for children and their families who are battling pediatric brain tumors and to raise awareness.

Yankees General Partner and Vice Chairperson Jennifer Steinbrenner Swindal, manager Joe Griardi along with players Ichiro Suzuki, Shawn Kelley, David Phelps, Adam Warren, David Robertson and Francisco Cervelli surprised Callahan as he entered the Hard Rock Café. Callahan had finished his last treatment earlier in the day and went to the Hard Rock Care from the hospital.

After an introduction by Girardi, Army Executive Athletic Director Bob Beretta officially welcomed Callahan to the Army team. He was presented with a football, jersey and hat from Mitjans and posted for photos. Callahan then enjoyed lunch with the players before departing for Yankee Stadium.

Callahan signed a one-day contact during a press conference with General Manager Brian Cashman at Yankee Stadium and then went to his locker in the Yankee Stadium clubhouse to change into his uniform before heading to the field.

The Friends of Jacyln Foundation came about in 2005 when Jaclyn Murphy became connected and later adopted as an honorary member of the Northwestern women's lacrosse team. She was diagnosed with medulloblastoma, a malignant brain tumor as a 9-year-old, and was part of the team as Northwestern won the school's first NCAA championship.

Jaclyn shared a big dream with her father, that she wanted other children with pediatric brain tumors to have similar experiences. Since then, the Foundation has continued the mission of improving quality of life and utilizes the mantra "live in the moment … play in the moment."

The Yankees' HOPE Week initiative is an organizational effort, integrating players, coaches, the Yankees front office, dozens of sponsors and some of New York's most iconic social and corporate institutions.

The initial phase of HOPE Week planning involves the selection of the honorees. In order to draw on the most diverse and inspiring group possible, an online nomination form is made available to the public on yankees.com. Additionally, the Yankees Media Relations Department reviews general fan mail and independently reaches out to other public social institutions to find exceptional individuals to recognize.

In addition to Yankees' HOPE Week and Friends of Jacyln Foundation, the Army football coaching staff is also involved with Lauren's First and Goal Foundation. Army assistant coach John Loose and his wife, Marianne, started the foundation in honor of their daughter, Lauren, a 17-year-old pediatric brain tumor survivor. The Foundation has raised more than $1 million toward its mission to provide financial support for brain tumor research and cancer services, to offer financial and emotional support to families living with pediatric cancer and to increase awareness of the disease.

Monken was the featured speaker and a bevy of Army assistant coaches and staff served as counselor's during the Pennsylvania Lauren's First and Goal Camp last month.