PHILADELPHIA -- Former Eagles Pro Bowl tight end Pete Retzlaff died Friday morning of natural causes, the team announced. He was 88.

"Pete was a revolutionary tight end and one of the most productive players in the history of our franchise," Eagles chairman and CEO Jeffrey Lurie said in a statement. "He was a five-time Pro Bowler, a key contributor on our 1960 Championship team, and of course his number 44 was retired after he established numerous receiving records over his 11-year career. But Pete's legacy goes far beyond the success he was able to achieve on the field. He gave so much to this organization and to our sport as a player, general manager, broadcaster, and leader of the NFLPA.

"He stayed connected with the team and the city of Philadelphia for many years after his retirement. I had the pleasure of spending time with Pete over the years and I will always remember him as a true gentleman who was kind and genuine and who connected so well with others. On behalf of the organization, our thoughts are with Pete's family and friends as we mourn the passing of an Eagles legend."

Retzlaff was a co-captain on the 1960 title team and one of just nine players in Eagles history to have his jersey number retired.

Retzlaff was originally selected in the 22nd round of the 1953 draft by the Detroit Lions but served two years in the Army and was claimed off waivers by the Eagles in 1956. He went on to play his entire 11-year career in Philadelphia.

One of the first tight ends to have both receiving and blocking prowess, Retzlaff still ranks second in franchise history in receiving yards (7,412), behind only Hall of Fame receiver Harold Carmichael.

"Pete was proud to have played his entire career in Philadelphia," the Retzlaff family said in a statement, via the Eagles website. "Our family can't thank the Eagles and the wonderful fans enough for their support that bolstered his playing years and beyond.

"Pete set lofty goals for himself. He believed in hard work, honesty, and always giving 100 percent effort. Throughout his life, he believed in giving back to the community as a thank you for what they gave to him. Thank you to all of Philadelphia."