Reacting swiftly to the news that standout linebacker Takeo Spikes had signed an offer sheet with the Buffalo Bills earlier in the day, the Cincinnati Bengals on Friday night struck two deals with veteran free agents to bolster their defense.

The Bengals reached contract agreements with defensive tackle John Thornton and linebacker Kevin Hardy, certainly two of the better unrestricted players at their positions.

The moves could signal the end of Spikes' five-year career with the club. Cincinnati has one week to decide whether to match a six-year, $32 million offer sheet that Spikes, a "transition" free agent, signed with the Bills. Even before the Friday acquisitions of Hardy and Thornton, the indications were that they would not match the offer.

In fact, Spikes phoned new head coach Marvin Lewis on Friday, and urged him not to match.

Hardy is the better known of the Bengals' two new defenders, but Thornton could have the better upside. The four-year veteran, who played his entire previous career with the Tennessee Titans, is an emerging young interior defender and, at age 26, could develop into a dominant player.

He signed a six-year, $22.5 million contract on Saturday. The deal includes a $5 million signing bonus.

"He loved his visit (to Cincinnati) and struck a real rapport with Marvin Lewis and (defensive coordinator) Leslie Frazier," agent Harold Lewis said of Thornton. "He flat-out told me to get a deal with them. Maybe this will send a signal to other players and agents that things are different with the Bengals. I know that John felt very strong about being part of the turnaround there."

Thornton was a second-round choice in the 1999 draft and the former West Virginia star has started in 36 of his 51 appearances. A staunch run defender, he has also flashed some pass rush ability and has 10½ career sacks.

Hardy, 29, is the likely replacement for Spikes, the team's leading tackler in four of his five seasons with the Bengals. The Bengals courted him heavily earlier this week.

There was a chance he would return to Dallas, where he played in 2002, but the Cowboys did not want to compete with the four-year, $14 million offer Hardy received from the Bengals and dropped out of the running. In a 2002 season when he revived his career after knee surgery the prior year, and re-established himself as a playmaker, Hardy had 114 tackles, two sacks, three forced fumbles and 10 passes defensed.

A first-round choice of the Jacksonville Jaguars in 1996, Hardy has 903 career tackles and 29½ sacks.

Len Pasquarelli is a senior writer for ESPN.com.