KANSAS CITY, Mo. -- The preseason hasn't been kind to the defense of the Kansas City Chiefs. Opponents have been able to run against the Chiefs, and last week the Los Angeles Rams went on two long touchdown drives against them when it was starters vs. starters.

Even the starting defense's big preseason play, Marcus Peters' end zone interception against the Seattle Seahawks and Russell Wilson two weeks ago, came on a play when Peters was beaten initially but Wilson threw the ball late, allowing the cornerback time to recover.

So even though it's merely halfway through the preseason, it feels like the Chiefs could use a lift, a lift that only the return of Tamba Hali could provide.

His aching knees have at long last allowed Hali to pass his physical and be removed from the physically unable to perform list. He will join the Chiefs at practice as a limited participant on Tuesday for the first time since last season ended.

In some ways, Hali is the Chiefs' spiritual leader. Many of their young players take their inspiration from a guy who has lasted until his 11th NFL season as much on his determination and effort as anything else. He'll make a positive difference from the moment he steps on the Chiefs' practice field.

But the Chiefs might want to temper their expectations for Hali, who turns 33 in November. His knees have been an issue for some time. He hasn't been able to practice much during the regular season in either of the past two seasons, though on game day he almost always showed up and played well enough to be worthy of his Pro Bowl berths.

Still, Hali's sacks were down, 6.5 last season and 6 the year before. Those are the second- and third-lowest totals of his career.

This is a new year, yet already the signs are somewhat ominous for Hali. He couldn't practice at training camp. Hali himself mentioned in March when he signed his new contract with the Chiefs that maybe it was time for a more limited role.

Then coach Andy Reid last week said the problems with Hali's knees are nothing that surgery can correct.

"He's getting up there in years and his knees are not in the greatest of shape," Reid said.

Judging from their comments, it certainly sounds like the Chiefs will have to manage Hali's practice time, perhaps save him for Sundays once the regular season begins. They may have to limit his playing time, too.

Other than that, the Chiefs know they can count on Hali being willing to play when the regular season begins and giving an effort that only he can.

The Chiefs might be wise not to count on much more than that, initially at least.