The case of San Diego Chargers defensive end Shawne Merriman, and here in Baltimore Kyle Boller, shows how difficult and tricky injuries can be for NFL players.

Merriman, the former Maryland star, is forgoing surgery on two knee ligaments that he will surely need at some point. He’s putting off the operation in order to play for the Chargers during a season when they feel they have a window of opportunity to contend for a Super Bowl.

If you read the stories about Merriman carefully, it would appear that the Chargers suggested that he have the ligament surgery after last season. But this is no minor procedure – it requires a six- to seven-month rehab – and the player elected to go with a less serious arthroscopic procedure that was unrelated to the ligaments. When training camp started, though, the knee started acting up.

After visiting a bunch of doctors recently, Merriman has decided to play wearing a brace and the coaching staff will have to pick its spots when to use him. Frankly, who knows what the right call should have been – either at the end of the 2007 season or now. These are medical dilemmas without absolute answers.

Here in Baltimore, the Ravens are still waiting to see how Boller’s shoulder injury -- which apparently occurred in the preseason game against Minnesota – works out. After Boller had an MRI, Ravens GM Ozzie Newsome said that surgery is not imminent.

"Kyle Boller could play again this season," Newsome said. "That could change, but this is good news."

Boller has not been throwing in practice and he will miss his second preseason game tonight when the Ravens play Atlanta.