Here's a sneak peak at our notebook for tomorrow ...

By Mark Craig

The NFL's replacement officials continued their preseason struggles in embarrassing fashion during the second quarter of the Vikings' 12-10 loss to the Chargers at Mall of America Field on Friday night.

Both blunders went against the Chargers, causing coach Norv Turner to waste two of his challenges within four minutes. Teams get two challenges to start the game and receive only one extra challenge if they win their first two. Turner easily won both of his challenges and never needed a third.

With 12 minutes, 27 seconds left in the half, Vikings running back Lex Hilliard clearly fumbled the ball away. But the closest official ruled him down.

A disgusted Turner whipped his red challenge flag high into the air before the Vikings had a chance to snap the next play into action. The ruling was overturned, giving the Chargers got the ball at the Vikings' 31-yard line. Seven plays later, they kicked a 34-yard field goal to take a 6-0 lead.

Four minutes later, at the 8:32 mark of the quarter, the officials blew another easy call when they ruled an interception by Chargers defensive back DeAndre Presley an incompletion. Presley was one of two defensive backs who jumped Christian Ponder's pass to Percy Harvin. There was no doubt the ball was caught by Presley. So Turner threw his flag again, this time just lobbing underhand onto the field.

Meanwhile, Vikings coach Leslie Frazier lost when he challenged a fumble by Derrick Coleman with 12:06 left in the game.

Vikings punter Chris Kluwe may have put it best after the game when he morphed back into @ChrisWarcraft and tweeted: "The NFL really needs to kiss and make up with the refs. These replacements are horrible. Frankly, it's kind of embarrassing."

Dire situation at safety

Starting safeties Harrison Smith and Jamarca Sanford were still on the field at the end of a meaningless preseason game because, well, the Vikings had no other healthy safeties to put out there.

Mistral Raymond experience lower-back tightness during pregame warmups and didn't play. Rookie Robert Blanton, who recently returned to practice after a hamstring injury, was held out and will get extra reps in Thursday's preseason finale at Houston.

Meanwhile, safeties Eric Frampton (groin) and Andrew Sendejo (ankle) also were injured. Also hurt Friday night were tight end Rhett Ellison (knee) and cornerbacks Josh Robinson (concussion) and Marcus Sherels (ankle). Frazier didn't know the severity of the injuries Friday night.

Smith can expect a fine

Smith was called for unnecessary roughness for a helmet-to-helmet hit on receiver Mike Willie with 1:35 left in the game. He can expect a fine from the league sometime in the near future.

"I thought maybe I could go for the ball, then I realized I should go for the hit, so I kind of got caught in the middle," Smith said. "I wish I didn't get the penalty. Maybe I could have played it differently. I'll watch the film. It's easy to watch on TV and say, `You should hit him here or there.'"

Chargers take a dive

After losing running back Ryan Mathews and receiver Vincent Brown to significant injuries in each of the first two preseason games, the Chargers deactivated 18 players, including seven starters, before Friday night's game. Six offensive starters didn't play, including quarterback Philip Rivers. Charlie Whitehurst started at quarterback.

Other starters inactive for San Diego were tight end Antonio Gates and the entire left side of the offensive line, including center Nick Hardwick, left guard Tyronne Greene and left tackle Jared Gaither. Rookie seventh-round draft pick David Molk started at center, while undrafted rookie Mike Harris started at left tackle.

"When you're playing against backups, you should dominate as a defense, and we did," defensive end Jared Allen said.

The Vikings had six sacks. Allen and linebacker Jasper Brinkley had two apiece.

As hard as they tried to avoid the weekly injury bug, the Chargers might have lost another key player. Linebacker Melvin Ingram, the 18th overall pick, had to be helped off the field with what the team called a thigh bruise.

Quick hits

--Deactivated before the game for the Vikings were receiver Kamar Jorden, cornerback Chris Cook, fullback Ryan D'Imperio, running back Adrian Peterson, tight end John Carlson, defensive tackle Letroy Guion and guards Bridger Buche and Geoff Schwartz. Chris Carr started in place of Cook at left cornerback. Eight other players didn't play, including offensive tackle DeMarcus Love (pectoral) and linebacker Larry Dean (shoulder).

--Peterson went through pre-game warmups in full pads before changing to watch the game from the sideline.

--Rookie Jarius Wright had the team's longest punt return of the preseason, a 24-yarder to the Chargers' 28-yard line, late in the second half. It led to a 29-yard field goal.

--Receiver Devin Aromashodu had his first catches of the preseason, finishing with three for 28 yards.