Centers Alex Mack of California, Eric Wood of Louisville and Max Unger of Oregon are widely considered the top three interior linemen in the draft. The Lions have done their diligence on each and could draft one with the first pick of the second round.

According to league sources, Lions offensive line coach George Yarno (along with Jaguars tight ends coach Mike Tice) ran Mack's pro-day workout at California last month, the Lions attended Unger's personal workout conducted by Broncos coaches days earlier (and sat down there for a private film session with him), and Wood is one of 30 prospects the Lions brought to Detroit for a physical and visit.

All three players are projected late first- or early second-round picks, and all have been busy crisscrossing the country recently. Mack has traveled to Cleveland, Baltimore, Pittsburgh and met with Atlanta general manager Thomas Dimitroff; Unger visited Pittsburgh on Tuesday; and Wood was expected in Cincinnati and Cleveland this week.

The Lions, who allowed a league-high 169 sacks the last three years, are looking for more physical linemen as they try and rebuild their offensive front. If they draft Georgia quarterback Matt Stafford No. 1 overall as expected and pass on Baylor tackle Jason Smith and Virginia's Eugene Monroe, they might find the most value in a versatile lineman like Mack, Wood or Unger at pick 33. Known primarily as centers in college, all three have the temperament to play guard in the NFL, the size the Lions covet (they're all at least 6-foot-3 and 309 pounds), and could revert back to center if the Lions decide not to sign Dominic Raiola to a contract extension.

So far this offseason, the Lions have re-signed guard Stephen Peterman and backups George Foster and Damion Cook, and added free-agent guard/tackle Daniel Loper in free agency.

One other visit note, the Lions hosted former Michigan tight end Carson Butler recently after tight ends coach Tim Lappano ran Butler's pro-day workout at Michigan last month. Butler is projected as a late-round pick or priority free-agent signing.

I point this out not to pick on the Lions – it's the way things are done in the NFL and, for that matter the world; you hire people you know and trust, either directly or through others you know and trust – but because it's hypocritical now for the same people who banged on Rod Marinelli for hiring ex-Tampa Bay assistants to praise Jim Schwartz for putting together the staff that he did: Every non-holdover assistant on the Lions' new staff has deep-rooted ties to Schwartz, offensive coordinator Scott Linehan or defensive coordinator Gunther Cunningham.

Linehan spent the last three years as head coach in St. Louis, where new quarterbacks coach Jeff Horton served as his offensive assistant. Offensive quality-control assistant Todd Downing also worked with Linehan the last three seasons at a variety of positions, and tight-ends coach Tim Lappano coached at Idaho when Linehan was a player there two decades ago.

Cunningham comes from Kansas City. So does assistant secondary coach and Harvard Law grad Daron Roberts. Defensive-line coach Bob Karmelowitz spent the last three years in Houston, but he was in in Kansas City for nine previous seasons, including six during Cunningham's tenure as defensive coordinator and head coach.

Assistant defensive-line coach Kris Kocurek didn't coach in K.C., but he played briefly as a defensive tackle for the Titans in 2001, when Schwartz was defensive coordinator and Cunningham assistant head coach. Linebackers coach Matt Burke spent five seasons with the Titans, the last three as a defensive quality-control assistant working alongside Schwartz.

Offensive-line coach George Yarno and secondary coach Tim Walton have less direct ties to Schwartz and his coordinators, but both worked under former Michigan State coach Nick Saban at LSU. Linehan spent one year with Saban in Miami, and Schwartz and Saban worked together for two years with the Cleveland Browns.

I think Schwartz did well in assembling the staff that he did. Cunningham is aggressive and a proven motivator. Linehan is a bright offensive mind with new perspective from his failed stint as a head coach. Their assistants should be in lockstep with what they're teaching and that's a must as the Lions rebuild. But, as Marinelli and plenty of others can attest, that doesn't guarantee success in the NFL.

Thanks to an e-mailer for alerting me to a story from the Fox affiliate in Memphis about Tigers defensive coordinator Tim Walton leaving to join the Lions as defensive-backs coach. I was covering the Michigan-Michigan State game last night and have not been able to confirm the addition yet, but there's no reason to believe it's not true.

Presumably, Walton and new Lions coach Jim Schwartz crossed paths in Tennessee, and even if they hadn't Walton worked under Nick Saban at LSU and we all know Schwartz's ties with Saban. (Incidentally, that makes at least three assistants with Saban ties in offensive coordinator Scott Linehan and offensive-line coach George Yarno.)

That leaves only the defensive line unaccounted for in terms of position coaches, and maybe quarterbacks coach, though Linehan will work closely with them and new tight-ends coach Tim Lappano also coached quarterbacks in his last stop at Washington. Rivals.com reported Lappano's hiring yesterday, and every other assistant has been in place for several weeks.

Expect the Lions to make an announcement on their entire staff by the end of the week. Perhaps then we'll find out what happened to Bob Slowik, who the Rocky Mountain News pegged for the Lions' secondary job last month.