One area that displeased Vikings head coach Mike Zimmer in the second half of Friday night's 10-6 preseason win over the Raiders was pass protection, but it was an issue during the first half, too.

The Vikings allowed six sacks on Friday night for a total loss of 41 yards, and that's not including another sack of Teddy Bridgewater that was negated by a defensive holding penalty on the Raiders.

On 12 passing plays, the first-team offensive line surrendered a pair of sacks and allowed four other pressures, according to Pro Football Focus, though some of those pressures came on the same play, like when center John Sullivan and right tackle Phil Loadholt were both beaten as the Raiders swarmed Matt Cassel for a sack on the first drive. To be fair, though, Bridgewater did not do them any favors when he held onto the ball in the red zone and was sacked and stripped in the pocket.

The Vikings' backups allowed four sacks and nine total pressures, according to Pro Football Focus.

Rookie left tackle Antonio Richardson, rookie left guard David Yankey and right tackle Mike Remmers were each beaten for one sack and right tackle Austin Wentworth allowed three hurries.

It was only one game — and a preseason game at that — and the offensive linemen still have time to iron out any wrinkles, whether they are technical errors or communication issues, before the season opener. But it something worth keeping an eye on considering the Vikings allowed 44 sacks in 2013 and gave up sacks on 8.1 percent of their pass attempts, which ranked 22nd in the NFL.