Chiefs OLB Tamba Hali returned to the practice facility on Monday, bringing with him some hope that the Chiefs will actually be able to make a defensive stop before the fourth quarter this Sunday in Buffalo.

Hali missed Sunday's opener against Atlanta because of a one-game suspension for breaking the NFL's substance abuse policy. Without their best pass rusher, the Chiefs rarely pressured Atlanta QB Matt Ryan, who had as much time as he wanted to find open receivers.

"We all know that Tamba brings a lot to the table as far as his ability to rush the passer," coach Romeo Crennel said Monday. "When you have that kind of pressure that you can apply to an opposing offense, that's good for us and bad for them. They have to be concerned about it. We'll get him back and hopefully he'll be at a level that he can impact the opponent and then be able to help us win some games."

The Chiefs will have pass rushers on both sides of the defense against Buffalo. OLB Justin Houston did get to Ryan a couple times on Sunday and recorded one sack. On the other side, Edgar Jones filled in for Hali on passing downs. Jones has 1.5 sacks in his six-year career and struggled to generate a pass rush. 

"Houston was in the quarterback's face along with the sack that he got," Crennel said. "He had some push on the pocket, but they were able to make the plays. But like I said, we were close on some. But we didn't make them."

Pass rush was not the only area where Kansas City's defense was lacking. The secondary was also a weak spot. The Chiefs were without CB Brandon Flowers along with starting S Kendrick Lewis.

Crennel said that Flowers (foot) and CB Jalil Brown (groin) would try to practice this week and see what they're able to do. Brown suited up but rarely played against Atlanta. Crennel had said on Sunday that Flowers would have to practice to play.

Crennel listed Lewis (shoulder) as limited at Monday's practice, along with starting NT Anthony Toribio (ankle) and DL Allen Bailey (ankle).

The Chiefs will have to execute a roster move on Tuesday to put Hali back on the roster. Hali was not counted as part of the 53-man roster during his suspension.

Follow Chiefs reporter C.J. Moore on Twitter @CBSChiefs and @cjmoore4.