The Oakland Raiders did not figure to risk injury to any of their star or front-line players in their preseason opener Saturday night, and they stayed true to that summation. Instead, it was a showcase for many of their second-tier starters and rookies trying to get a feel for hitting someone else in another jersey. It did not exactly go well for them in a 20-10 loss to the Arizona Cardinals in Glendale, Arizona.

QB depth chart: EJ Manuel appeared to maintain his hold on the No. 2 gig over Connor Cook. Manuel completed 10 of 12 passes for 102 yards while playing the entire first half. Cook, meanwhile, looked uneasy early in the second half and finished 10-for-21 for 82 yards. Derek Carr need not look over his shoulder.

When it was starters vs. starters, the Raiders looked ...: Well, it was hard to make an assessment here considering so many Oakland starters did not play, from Carr to running back Marshawn Lynch, to receivers Amari Cooper and Michael Crabtree, to defensive end Khalil Mack, to outside linebacker Bruce Irvin. But consider this -- the Raiders’ primary backups were outscored 17-0 by the Cardinals’ first- and second-stringers.

One reason to be concerned: The Raiders still have issues at middle linebacker because their starting middle linebacker, fifth-round draft pick Marquel Lee, played, well, like a fifth-round rookie. True, he did flash a couple of times, from breaking up a pass across the middle to picking up a fumble. But he struggled in coverage against tight ends -- sound familiar? -- and got pushed around at other times. He was wearing the green “communications” dot on his helmet, too. Another reason? The Cardinals were a staggering 13-of-19 on third down.

That guy could start: Well, if we’re talking linebackers, LaTroy Lewis came out of nowhere to record a pair of sacks, even if it was against third-teamers and guys who won’t make 53-man rosters. Then again, rookie defensive tackle Treyvon Hester also had two sacks, and the seventh-rounder was running with the first-team defense heading into camp, before fellow rookie Eddie Vanderdoes overtook him at the beginning of training camp.

Rookie watch: We already went over Hester’s two-sack exploits, so what about seventh-round safety Shalom Luani? The rookie nearly pulled off the play of the day with an acrobatic interception of Drew Stanton near the goal line. Luani went high and cradled the ball with an outstretched hand, then he came crashing down and the ground knocked the ball out. Almost.

Marshawn Lynch sits: Even if the erstwhile Beast Mode suited up but did not play, he may have made the most news. In his return to the NFL, Lynch sat during the national anthem. In an apparent protest reminiscent of Colin Kaepernick’s last season to bring attention to racism and police brutality, Lynch remained seated during the anthem on a cooler. Later, during the game, he borrowed a sideline photographer’s camera to purportedly snap some shots.

Clive Walford shows up: He is seen as the pass-catching tight end on the roster, Lee Smith is viewed as the blocking tight end, and Jared Cook is perceived as the most well-rounded tight end. Walford had the play of the game, per the team’s broadcast -- a 30-yarder down the seam. He finished with three catches for 44 yards.

Karl Joseph shows pop: The Raiders’ first-round draft pick from 2016 showed the thump that has been promised of him since last season with a first-half hit. The strong safety came flying in from the back end to lay the wood on David Johnson at the line of scrimmage, giving Raiders fans a sense of what they hoped to see last year.