During an appearance Thursday afternoon on ESPN's "NFL Insiders," Cincinnati Bengals coach Marvin Lewis gave a couple of quick injury updates.

Three key injured offensive players are "all progressing well," Lewis said.

Specifically, he was referring to offensive tackle Andre Smith, tight end Tyler Eifert and receiver Marvin Jones. Each of them ended up on season-ending injured reserve after dealing with a series of serious injuries.

Smith was lost after Week 12 following a triceps injury he suffered while trying to block the Houston Texans' JJ Watt. Eifert originally was designated for return after dislocating his right elbow in the season-opening win at Baltimore. He remained on IR throughout the season, though, because the elbow took longer to heal than expected. As a result of that, the Bengals felt it was wise Eifert eventually be shut down and for him to undergo shoulder surgery to clear another injury that had nagged him as far back as last offseason.

Eifert told reporters the day after the Bengals' Jan. 4 playoff loss that he thought he doubted he would be 100 percent by minicamp, but he expected to participate fully in training camp.

Unlike Smith and Eifert, Jones didn't suit up at all this season after suffering an ankle injury while training last offseason. He ended up breaking a foot later in the year during training camp. Once the foot injury cleared, though, the ankle still was enough of an issue in the middle of the regular season that the Bengals shut down the player who was their second-leading receiver the year before.

The Bengals are hopeful injured linebacker Vontaze Burfict can progress as well as it appears these others have so far. The Pro Bowler underwent microfracture surgery earlier this month. It's a procedure that doesn't have a great track record as far as allowing athletes to get back to their same level of production once they recover from it. Some can. In order for Burfict to be among the fortunate few, he will have a long and grueling several months of rehab.

Earlier this week, the doctor who performed the surgery expressed optimism Burfict could be back by training camp.

"He's got a hard road," Lewis said on "NFL Insiders." "As I've said publicly, because I keep putting it in his ear, he's got to work his tail off. He worked hard to get to the NFL, he's got to work harder to get back to that level."