HENDERSON, Nev. — The first day of pads is a weighty day for offensive lines across the NFL. The pressure was particularly heavy on the Las Vegas Raiders’ front as contact in training camp began on Monday.The group was one of the league’s worst units a season ago. The Raiders allowed the most sacks (64) and the fifth-highest pressure rate at 40.5%, according to TruMedia. Their futility carried over into run-blocking as well; they produced a league-worst 30.4% rushing success rate and forced Ashton Jeanty to gain nearly all of his yards after contact. The line’s struggles were a major reason the Raiders won just three games — improvements had to be made.In the first real test of growth, Las Vegas’s offensive line received a passing score. They held up well for the most part against the pass rush, creating solid pockets for Kirk Cousins. And they produced solid gaps for Jeanty to run through; those were few and far between during his rookie season. Jeanty said he spent the first days of camp building chemistry from the line, observing how everybody blocks and moves.“When the pads come on, it’ll be a lot easier,” Jeanty said.That ease was certainly aided by the team’s offseason upgrades. Center Tyler Linderbaum, signed to a record contract for the position in free agency, looked like an anchor in the middle, springing a few runs free and preventing pocket collapse. Both the front and Jeanty looked better adjusted to head coach Klint Kubiak’s zone rushing scheme than the disjointed system then-offensive coordinator Chip Kelly installed last year. Gaps were forming organically, and Jeanty was patient for them to develop before bursting through.“In general, I think the offensive line is doing a good job of coordinating together,” defensive lineman Thomas Booker said. “Offensive line is a job that requires a lot of teamwork, communication and coordination… There’s a lot of guys on the offensive line that are making strides, I think the whole team is doing a good job of communicating.”Raiders players trending up, downSam WarrenIt wasn’t a walk in the park by any means for the group, however. Both the first and second units allowed sacks during team drills. Maxx Crosby beat right tackle DJ Glaze and left tackle Kolton Miller for a pair of would-be takedowns. Tonka Hemingway continued his strong start to camp by penetrating the middle to get after Cousins on a play. And, against the twos, Benito Jones was the beneficiary of strong coverage that gave him time to meet Fernando Mendoza in the backfield.Such is training camp. Defensive tackle Jonah Laulu described it as “iron sharpening iron,” the oft-used adage by coaches of the Shanahan tree. Laulu furthered it by saying the mutual growth has continued after the whistle as well.