TEMPE, Ariz. -- The Arizona Cardinals' starting offense has been impressive through two preseason games, although serious questions remain unanswered at three spots on the line.

The unit has scored on its opening possession in each game. In a loss to the Vikings Saturday night, the Cardinals went 94 yards. The week before, it went 79 yards.

In both, the Cardinals revealed what could be a terrific passing attack, provided quarterback Carson Palmer gets protection.

Against Houston in the opener, Palmer went 5-for-5. Included were passing plays of 25 and 38 yards. Against the Vikings, receiver Jaron Brown took a short screen pass 51 yards.

"It's good to come out fast and have some really nice running plays, convert on third downs," Palmer said. "Good execution, good efficiency, which is what you want out of these games."

The Cardinals' depth at receiver has been evident in both. Against Minnesota, Larry Fitzgerald had an acrobatic catch early, then left the game after a quarter. Michael Floyd is nursing a groin strain and didn't play but he's expected back this week.

In Floyd's absence, Brown has impressed. In two games, he has only four catches. But he has 101 receiving yards. One of the catches was for a touchdown and the other three helped set up scores.

"Big play every day," is how coach Bruce Arians described Brown's performance in training camp. "I don't care if it's Patrick (Peterson), Cro (Antonio Cromartie), who's on top of him. He's really developing a confidence factor to become a really solid player."

It's becoming more apparent every day that if the Cardinals can get solid play up front, this offense will be much improved over a year ago. That is a lot to ask, but the expected starting five has yet to start a game together.

Left guard Jonathan Cooper wasn't playing well before he suffered a turf toe injury that's caused him to miss a week of practice. His replacement, Earl Watford, has never played an offensive down in the NFL.

Center Lyle Sendlein has missed most of camp with a calf strain but is expected back this week. Right tackle Bobby Massie has played well through the preseason but he spent most of last season on the bench.

Keeping Palmer upright and healthy will be vital this season. It's evident he is comfortable now in Arians' system. The indecision and miscommunication that marred the first half of last season is gone.

This will be a critical week for the line's development. Sendlein is due back. Cooper might be. Watford played a lot last week, so he knows what he has to work on.

--Offensive tackle Max Starks apparently aggravated an ankle injury and left Saturday's game against Minnesota. He is likely to miss some practice time.