Blechen (tendinitis), defensive ends Trevor Reilly (knee), Nate Orchard (back) and Jason Whittingham (shoulder) and defensive back Wykie Freeman (knee) are just a few of the defensive players sidelined by injuries.
On the field, the defensive lineup has been a mishmash of younger players and backups.
The good news is all of them are expected to be at full strength by August. Despite the gaping holes, Utah's coaches aren't worried the starters' absences will hurt Utah's defensive cohesiveness.
If anything, the Utes are confident their defense will be as strong as always, no matter who suits up and who plays where.
As much inconsistency as the offense has had over recent seasons, Utah's defense has benefited from little changeover, contributing to the confidence defensive coordinator Kalani Sitake feels in his unit.
"Coach [Morgan] Scalley and I have been on the team a long time and we've worked well together, and coach Whittingham started this so having that consistency and how we work together has been important," Sitake said. "The last couple of years we've been able to break in safeties, corners and defensive ends and now we have the younger guys coming along, but we know how to work together and develop them."
Utah had several defensive issues to address heading into spring practice, not the least of which was replacing two NFL-bound linemen in Joe Kruger and Star Lotulelei.
The Utes also needed to find new cornerbacks and add depth at safety.
It sounded like a big task, even for a seasoned crew, but the Utes are happy with the way the players have developed. Sitake and the other coaches simplified some of the defensive schemes, allowing the players to "not think, just play," as sophomore linebacker Jared Norris put it, but the players have put in the work too and are showing it on the field.
"Every day they've gotten better," Sitake said. "Our older guys aren't getting a lot of reps and they are going up against a good offense, but the younger guys are doing fine."
Despite the loss of Lotulelei and Kruger, the Utes are confident their line has the talent to be just as good as it was in 2012, if not better.
Utah coach Kyle Whittingham referred to senior Tenny Palepoi, Lotulelei's replacement, as one of the top linemen in the league while freshman Stevie Tu'ikolovatu has been one of the standouts of camp.
"Our tackles have probably been the most improved group of spring," Whittingham said. "When we get the players from the recruiting class in this fall, we should be very deep."
The cornerbacks for now are Keith McGill and Justin Thomas. McGill has the potential to be one of the better playmakers in the league if the Utes can keep him healthy, while Thomas has emerged as a surprise player with the freshman beating out junior college transfer Justin Thomas so far.
The safeties are solid with Eric Rowe and Tyron Morris-Edwards having good springs. The addition of junior college transfer Tevin Carter in the fall should allow the Utes to keep Blechen at linebacker.
While their names might not be as well known as the Krugers or Lotulelei, Sitake believes with time they will be.
"We've got a lot of talent," he said. "We just need to take advantage of every practice we have to develop it."
2012 Utah defense
Nat'l rank Average
Scoring 49th 25.08
Pass defense 59th 235.3
Rushing 24th 129.0
The biggest name • With Star Lotulelei and the Kruger brothers having departed, who could be Utah's next big name? So far, tackle Tenny Palepoi seems to fit the bill at 6-foot-2, 300 pounds.
The biggest surprise • Freshman Stevie Tu'ikolovatu, a 6-1, 320-pound lineman, has exceeded coaches' expectations this year. Right now he is slotted as Palepoi's backup at tackle.
The biggest question mark • Senior Keith McGill has been hampered by injuries during his career, so the Utes must keep the corner healthy since the position remains one of the ones with the least experience.