It certainly wasn't ideal for the Vikings to finish Friday's 12-10 preseason loss to the Chargers with starting safeties Harrison Smith and Jamarca Sanford still on the field. But it was by necessity.

In pregame warmups, Mistral Raymond had suffered a back injury. Then in the second half, Eric Frampton strained his groin and Andrew Sendejo suffered an ankle sprain. The only other remaining safety who could have played late Friday was rookie Robert Blanton, who is still working back from his own hamstring injury. He was held out against San Diego; the Vikings plan to use him extensively in the preseason finale Thursday in Houston.

It's highly unlikely either Smith or Sanford -- or any other legitimate starter -- will play in that game. Which means coach Leslie Frazier may have to get creative with his lineup combinations. Or the Vikings may have to find an additional body or two somewhere else to finish the preseason with enough safety depth to survive.

It's uncertain whether Frampton or Sendejo will have enough recovery time to be ready for a Thursday night game. And while the Vikings were relieved Raymond's back problems were diagnosed as spasms and nothing more, he likely will not play against Houston either.

Fifteen players waived

The deadline for the Vikings to cut their roster from 90 players to 75 is Monday afternoon. But the Vikings felt no need to procrastinate, waiving 15 players Saturday. That included four wide receivers: Kerry Taylor, Bryan Walters, A.J. Love and Kamar Jorden. The others let go were linebackers Solomon Elimimian and Tyler Nielsen, running back Derrick Coleman, guards Bridger Buche and Grant Cook, cornerbacks Chris Stroud and Corey Gatewood, defensive ends Anthony Jacobs and Ernest Owusu, defensive tackle Tydreke Powell and offensive tackle Levi Horn.

Injury update

Rookie tight end Rhett Ellison left Friday's game because of a knee injury. But after undergoing an magnetic resonance imaging exam and additional tests after the game, the Vikings determined Ellison was suffering from a mild case of patellar tendinitis. He is not expected to miss much time.

Also injured Friday were cornerbacks Marcus Sherels (sprained ankle) and Josh Robinson (concussion).

Flag day

After what had been a pretty clean preseason, the Vikings committed four turnovers and had six penalties Friday. The most costly flags came against Smith and Zack Bowman, a pair of players typically lauded for their intelligence. Bowman was called for holding on a second-quarter kickoff that negated what would have been a 68-yard Sherels return.

Smith's unnecessary-roughness penalty -- for leaving his feet and launching himself into receiver Mike Willie on a third-down play -- kept the Chargers' game-winning field goal drive alive.