PHILADELPHIA — Eagles Hall of Famer Chuck Bednarik remained in serious condition at a Bethlehem-area hospital Thursday, two days after experiencing shortness of breath, according to a St. Luke’s Hospital spokeswoman.

However, the 85-year-old Bednarik was improving and was “sitting up in bed and talking” as of Thursday, his son-in-law Ken Safarowic said.

“They’re still running tests on him,” said Safarowic, who is acting as a spokesman for the Bednarik family. “It’s not a heart attack. His heart is as strong as when he was playing. But I think he’ll be in the hospital for a couple more days.”

Nicknamed “Concrete Charlie,” Bednarik was one of the last true 60-minute men, having played both center and linebacker for most of his 14 seasons in the NFL. He played for the Eagles from 1949 to ‘62 and was an all-pro 10 times. The former Penn star was voted into the Pro Football Hall of Fame in 1967.