"With the ACL, you have to decide whether or not you're going to have to fix it through ACL reconstruction or don't fix it," Burkholder said.
Either way, Kelce is out for an extended period. Coach Andy Reid said that Dallas Reynolds, who replaced Kelce after he left in the third quarter of the Baltimore game, will make his first career NFL start Sunday at Arizona.
Reynolds, who spent the previous three years on the practice squad, played his first downs at center in the Eagles' 24-23 comeback win over the Ravens. He played 37 snaps and avoided any major mistakes. Reid said Reynolds would assume the same pre-snap responsibilities that Kelce held.
"I've been looking forward to this moment for a long time," Reynolds said. "A few years on the practice squad and now to be active and now to have a chance to play and start - I'm excited for the opportunity."
The Eagles likely will be missing another starter on the offensive line against the Cardinals. Reid said that left tackle King Dunlap, who suffered a hamstring strain, was a long shot to be ready. Demetress Bell, who opened training camp as the starter but lost the job after the first preseason game, will start if Dunlap cannot play.
"I was very pleased with how Bell played," Reid said. "I thought he did a heck of a job and worthy job to start, and he's got a lot of experience under his belt to do that."
The absence of Kelce and Dunlap would mean the Eagles are down to seven healthy linemen. Rookie Dennis Kelly would back up right tackle Todd Herremans and Bell. He also can play both guard spots. Nate Menkin, whom the Eagles acquired just weeks ago, also can play tackle or guard.
But neither would be the ideal backup at center. The team is likely to add a body this week, probably Tuesday after Kelce's fate is known. On Monday, the Eagles brought in Steve Vallos, whom they released before the opener. They are likely to sign him Tuesday, an NFL source said. If they don't, they could pursue Julian Vandervelde, who initially made the team but was cut the next day. He is now on the Tampa Bay practice squad. The Eagles could try to sign him. Jamaal Jackson, the Eagles' starting center from 2005 to '09, was Kelce's backup last season and is not on an NFL roster.
Jackson did not mesh with line coach Howard Mudd's blocking methods and did not take part in training camp, so he is unlikely to return.
Kelce will not be easy to replace. The Eagles could wait until October to decide on his future. Burkholder said that waiting until the MCL heals before scheduling surgery on the ACL would provide a better result.
He admitted that there was some division within the medical field on how to proceed when there are combined ligament tears.
"There's not a consensus around the country among sports medicine people," Burkholder said.
Daniel Kharrazi, an orthopedic surgeon at Kerlan-Jobe Orthopaedic Clinic in Los Angeles, said that some surgeons prefer to correct both ligament tears at the same time. If the Eagles elected to let Kelce play with the partially torn ACL, there is the risk of a complete rupture, Kharrazi said.
"Usually combined ligament injuries are much tougher than single," said Kharrazi, who spoke generally, having never examined Kelce. "With an MCL, you have a pretty good idea of what's going to happen. When you have a combined, it's a different story."
Burkholder said there have been examples of other NFL players with similar injuries returning to play within weeks.
"It's a mixed bag," he said. "Some people get it fixed right away, and some people just let the MCL heal and play with a partial."
The Eagles can place Kelce on injured reserve and still bring him back if they deem him ready to return. Each NFL team can activate one player per season off the IR list.
Eagles news as it happens:
On Birds' Eye View: philly.com/bev
Jeremy Maclin not ruled out for Sunday after second hip pointer injury. D3.
Vilma: Meeting with commissioner "truthful." D4.
Contact Jeff McLane at 215-854-4745 or firstname.lastname@example.org. Follow on Twitter @Jeff_McLane.