By NATE ATKINS -- natkins@mlive.com

Eric Ebron is out. After failing to find the trade compensation they wanted, the Lions have released their enigmatic former first-round tight end.

The move saves $8.25 million but creates a sizeable hole in the offense. Not only is Detroit down to second-year man Michael Roberts and developmental piece Hakeem Valles at the position, but they are without a true 'F' tight end to outrun linebackers up the seam. That's been a critical component of Jim Bob Cooter's and the Patriots offenses.

So now, the Lions will be on the lookout for a replacement. They could wait for the draft, where prospects such as South Dakota State's Dallas Goedert and Oklahoma's Mark Andrews intrigue. But tight ends take time to develop, so Detroit might be more tempted to find someone ready to go.

Here are a few possible replacements the Lions could consider signing:

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Tyler Eifert, 27, Bengals

The free-agent market does have one 'F' tight end who has reached the Pro Bowl and totaled 13 touchdowns in a single season. That's Eifert, a first-round pick from the draft before Ebron. At 6 feet 6 inches and 250 pounds, Eifert has the size and speed combination the Lions would love, but his availability is a major concern. In five seasons, he's never played a full slate of games, and he's missed at least half of three of the campaigns. He played in two games all of last season. The Lions would do some thorough medical tests before signing, but the constant recurrence of injury -- even in the Pro Bowl -- would make this move a major gamble.

UPDATE: Eifert re-signed with the Bengals.

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Julius Thomas, 29, Dolphins

Shortly after the Lions released Ebron, the Dolphins cut their 'F' tight end. Julius Thomas has disappointed the past few years, but Miami is also shedding cap space at a rapid rate, so talented players become the casualties. The 6-foot-5-inch, 262-pound Thomas has shown what he can do with back-to-back seasons with 12 touchdowns in 2013 and 2014 with the Broncos. One of the assistants on that offensive staff was Lions offensive coordinator Jim Bob Cooter. Could Cooter see something in Thomas, a two-time Pro Bowler who was once thought of highly enough to earn a five-year deal?

Detroit would be his fourth team in five seasons, which says plenty about the risk involved. He can't block even the worst of linebackers. And he has some of the same immaturity concerns that have haunted Ebron. The advantage to Thomas would be that he'd come so much cheaper than Ebron would have under the fifth-year option.

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Austin Seferian-Jenkins, 25, Jets

If the Lions want to dump one young, talented and questionable tight end for another, they can give a look to Seferian-Jenkins. At 6 feet 5 inches and 262 pounds, he's similar to Ebron in the sense that he's long had potential he just hasn't tapped into yet. He's yet to play 16 games, and he could be on his third team already. His issues were tied to alcoholism, which got him arrested and then released by the Buccaneers in 2016. He's since gone to rehab and is supposedly more than a year sober. Last season was his best yet, with 357 yards and three scores in a bad Jets offense. He seems to be turning his life around for the better, and that's brought him a market with interest already from the Jets, Seahawks and Jaguars.

UPDATE: Seferian-Jenkins signed with the Jaguars.

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Luke Willson, 28, Seahawks

If the Lions are looking for an option without as much risk, Willson could attract. He wasn't used as much as he could have been in Seattle, which struggled to pass protect and added Jimmy Graham to the mix a couple years ago, but he measures 6 feet 5 inches and 254 pounds and ran a sub-4.5-second 40-yard dash at his Pro Day back in 2013. He's had some injury issues, too, but he's played at least 14 games in four of five seasons and played in every game last year.

Willson would be a bet on potential because he never posted more than 362 yards or three touchdowns in any season in Seattle. But the proven option is off the market already after Graham signed his deal with the Packers.

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Martellus Bennett, 31, Patriots

The Lions had to try to defend Bennett for a few years when he was at his best, reaching the Pro Bowl with 916 yards in 2014. That was a high. So was winning a Super Bowl with the Patriots in 2016, when he caught 701 yards and seven scores. The lows have outweighed them so far, from multiple trades and ugly departures to other malcontent with organizations. The Patriots straightened him out for the Super Bowl season, which makes him an easy connection for Detroit now, but he didn't produce in his return there last year when he was dealing with a shoulder injury. When healthy, he's a strong and passionate receiver and blocker. If he passes a physical, he could be worth a flier, but he can be hard to trust.

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What if they don't sign anyone?

The Lions will be adding to this room, but it's possible they could wait until the draft. Again, Goedert and Andrews provide some intriguing options, though tight end would just be one more need to add to the list with only six picks to work with. Tight ends take time to learn the position before they can be effective, especially in an offense that audibles as much as Detroit's does.

The Lions do have Michael Roberts in the wings, and they have definite plans for the player they plucked out of Toledo in the fourth round last year. Roberts has red-zone potential but was incredibly raw as a receiver last year, catching just four passes. They like the potential of Hakeem Valles as well after holding onto him last season, but it's hard to imagine them trusting either to take on an important role, especially one that works vertically.

It's always possible Detroit tinkers with the offense to move away from the 'F' tight end role toward something more traditional. They do have a new tight ends coach and are installing a new running game. It would just go away from the tendencies of the Patriots, where coach Matt Patricia hails from; and the offense Cooter has run forever, particularly with strong efficiency with Stafford. This seems like too dramatic of a shift.

The likelihood is that the Lions have a target for this kind of role that they think they can get. Who it is and when he comes remains up in the air, but the next few days of free agency might be telling.