Free agent TE Kevin Boss (concussions) hasn't been medically-cleared to play.

Boss, 29, has suffered at least four serious concussions since entering the league in 2007, and his latest one came in Week 2 last season. Once a promising red-zone threat with the Giants, Boss' career has gone off the tracks.

The Chiefs listed TE Kevin Boss' release with a failed physical designation.

Chiefs released TE Kevin Boss.

Signed to a three-year, $9 million deal early in free agency last year, Boss suffered a season-ending concussion in Week 2. He finished with just three catches. Boss has a long and winding concussion history, suffering no fewer than four during his NFL career. The former Giant and Raider could be at the end of the line after failing to gain medical clearance last season.

Chiefs TE Kevin Boss (concussion) is out for the season.

Doctors told Boss that they wouldn't be able to clear him at any point this season. It's not a surprise for a player with at least four serious concussions on his resume. Boss' first season in Kansas City ends with a 3/65/1 line in three games. He's due $2.4 million in base salary in 2013.

Chiefs declared TE Kevin Boss, NT Anthony Toribio, FS Kendrick Lewis, WR Devon Wylie, CB Jacques Reeves, QB Ricky Stanzi and TE Jake O'Connell inactive for Week 3 versus the Saints.

Boss has a history of concussion and appeared to have sustained one in Week 2. Steve Maneri will fill in as the second tight end alongside Tony Moeaki. The Chiefs defense has struggled without Toribio and Lewis the first two games.

Kevin Boss (head) has been ruled out for Week 3 against the Saints.

Boss was injured in Week 2 against the Bills after S Da'Norris Searcy laid a wicked forearm to the front of the Boss' helmet while he was making a 29-yard catch. Boss has five catches for 91 yards in the season's first two weeks. Tony Moeaki will handle tight end duties. He is not a fantasy option.

The Chiefs confirmed that TE Kevin Boss sustained a head injury during the Week 2 loss to the Bills.

Boss took a wicked shot from Bills S Da'Norris Searcy and did not return. Searcy was penalized for unnecessary roughness. Boss has a history of concussions, leaving his Week 3 status very uncertain.

Kevin Boss left Sunday's Week 2 game against the Bills with an apparent head injury.

Boss caught a 29-yard pass deep down the middle and took an elbow to the head while falling to the ground from Bills safety Da'Norris Searcy. He walked off the field under his own power but looks questionable to return. Searcy was penalized on the play.

Kevin Boss had four catches for 62 yards in the first half of the Chiefs' second preseason game.

Chiefs agreed to terms with TE Kevin Boss on a three-year, $9 million contract.

After watching Bill Belichick and Josh McDaniels embrace the two-tight end attack, new Chiefs coordinator Brian Daboll, formerly a Patriots assistant, will install one of his own. Boss will be the inline tight end with Tony Moeaki (ACL surgery) ticketed for the more versatile "Joker" role. From a fantasy standpoint, Moeaki has the higher ceiling, though neither player is likely to exceed TE2 production.

Free agent TE Kevin Boss will visit the Chiefs on Thursday.

Not technically a free agent until 4PM ET Wednesday, Boss has reportedly drawn interest from "several teams." One year removed from back-to-back 500-yard campaigns, he won't last long in a thin tight end market.

Raiders released TE Kevin Boss.

It's a surprising move barely six months after the Raiders handed Boss a four-year, $16 million deal, but hardly unwarranted after he caught just 28 passes for 368 yards his first season in Oakland. New GM Reggie McKenzie appears committed to cutting away the waste of the final days of the Al Davis era. A natural landing spot for Boss would be his former Giants, who are in danger of being without both Jake Ballard and Travis Beckum next season as they recover from torn ACLs.

The Contra Costa Times' Steve Corkran expects TE Kevin Boss to be back with the Raiders in 2012.

Signed to a four-year, $16 million deal in August, Boss caught just 28 passes for 368 yards and three touchdowns this season, but will make only $2 million in 2012. With Carson Palmer having little history of featuring his tight ends, Boss won't be a good bounce-back candidate in fantasy leagues next season.

Kevin Boss caught three passes for 33 yards and a touchdown in the Raiders' Week 17 loss to the Chargers.

Boss finished his first season in Oakland with 28 catches for 368 yards and three scores. He was an asset as a blocker, as usual, but Hue Jackson doesn't use tight ends much in his passing game, and nor does Carson Palmer have a history of doing so. Boss will be low on the TE2 fantasy radar in 2012 leagues.

Kevin Boss caught three passes for 47 yards against the Lions in Week 15.

The king of garbage time was an afterthought for three quarters, catching two of his three passes in the final 40 seconds to set up a 65-yard field-goal attempt for Sebastian Janikowski. Boss is still not a reliable fantasy option versus the Chargers in Week 16.

Kevin Boss caught five passes for 43 yards and a touchdown against the Packers in Week 14.

Chalk it up to garbage time. Four of Boss' five receptions came after the Packers were up 31-0, and his fourth-quarter touchdown was the result of a disinterested defense. Don't bother picking up Boss for Week 15 against the Lions.

Kevin Boss (hip) is practicing fully this week.

He'll be active against the Packers. Splitting snaps with Brandon Myers of late, however, he's well off the fantasy radar despite Oakland's dearth of healthy pass catchers.

Raiders TE Kevin Boss (hip pointer) is day to day.

Coach Hue Jackson was confident that Boss would be able to play against the Packers. The ex-Giant is averaging 1.7 catches for 24.5 yards on the season.

Raiders TE Kevin Boss did not finish Sunday's game due to a hip pointer.

Backup Brandon Myers finished with three catches for 33 yards on Sunday, and if Boss is going to miss time then Myers will threaten to have low-end TE2 value.

Kevin Boss hauled in just one of his five targets on Sunday against the Dolphins for a total of eight yards.

Boss had two bad drops, while fellow tight end Brandon Myers outproduced him with three catches for 33 yards. Even if you combined the two players, there wouldn't be anything but low-end TE2 value.