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Jim Schwartz insists he isn't trying to send any of his players a message. However, the Lions coach is looking at some veterans to try to bolster the club.

After bringing in four defenders following a poor performance Thursday at Cleveland, the Lions signed offensive tackle Kevin Haslem.

Haslem, who has played 10 games in a three-year career, is now with his fifth NFL team. He was released by the Patriots last week, and the Lions picked him up to replace tackle Austin Holtz.

"I think you can say the same thing about Kevin that we said about the defensive guys," Schwartz said Sunday after practice. "When you can get a young veteran in at this point in camp, you get a couple weeks to look at him. That's helpful for everyone — both him and us."

No matter what Schwartz says, though, the influx of new players should have some players looking over their shoulders. The Lions started the process on Thursday, picking up 34-year-old defensive tackle Justin Bannan, who has spent most of his career with the Bills and Ravens.

Another defensive tackle, John Drew, was brought in on Friday, and on Saturday the Lions picked up two more experienced players. Linebacker Rocky McIntosh is a seven-year veteran who played most of his career with Washington before spending last season with the Rams.

The prize of the collection, though, is Rashean Mathis. Mathis has 30 career interceptions, all with Jacksonville, and he played in the 2006 Pro Bowl. His career hasn't been the same since a torn knee ligament late in the 2011 season, but Schwartz is willing to take a chance on a player who could help Detroit's iffy secondary at either cornerback or safety.

"He had a bump a couple years ago with the knee injury, and unlike some guys who can come right back, it still affected him last season," Schwartz said. "But he had a great workout for us, and we're convinced he's completely healthy. He's a smart player, and he's versatile, which is something we always want. He'll get some reps at corner and he's played at the nickel, as well."

Mathis worked out for the Lions on Saturday morning. He signed a contract and then practiced on Saturday and Sunday.

"There's nothing new under the sun," he said. "I've been around and I've seen it all, so I'm just looking to get plugged in wherever they need me. I could play safety, I could play corner and I can play nickel. I guess, at this point, I'm what you call a savvy vet."

McIntosh and Bannan are the same type of player — veterans who can quickly get up to speed and fill a hole on the defense without needing weeks to learn the system. Bannan will compete for a job behind Ndamukong Suh and Nick Fairley.

"His forte is stopping the running game," Schwartz said. "We've been working with him for a while, and we need to be able to rush the quarterback, but he's played in a lot of different schemes. He's been a 4-3 tackle and a 3-4 tackle, so he's a guy that can give some depth."

That's the reason behind signing McIntosh, and Haslem, to a lesser extent.

"These are veteran players who have a proven track record in the NFL," Schwartz said. "The only message here is that we're going to keep trying to keep signing good football players. None of this is a reaction to any one player's performance or bad preseason games. These are guys that we think could help our football team."

NOTES: Cornerback Chris Houston sat out most of Sunday's practice to rest a banged-up body. He was replaced by Chris Greenwood, who is still working his way back to full health after a hamstring injury. ... Louis Delmas (knee) missed another practice, but Schwartz remained hopeful that the oft-injured safety will be back in action on Monday. ... QB Shaun Hill was also limited, while John Drew, Cory Greenwood, Ross Weaver and Jason Jones missed the entire practice.