NAPA, Calif. _ The Raiders are awaiting word on the status of right guard Gabe Jackson, who was carted off the field with a leg injury during Thursday's joint practice with the Los Angeles Rams.
Jackson is one of the Raiders most consistent lineman, and the hope was teaming him with Trent Brown would be create of the NFL's most effective tandems on the right side of the line.
"We're concerned, obviously, really concerned about him," Raiders coach Jon Gruden said. "We'll get more information here when we can be specific for you. I don't want to speculate."
According to one source with knowledge of the situation, "It doesn't look good."
Jackson's mishap was the first potentially major injury of camp. Wide receiver Antonio Brown missed practice again with what is believed to be a condition similar to frostbite on both feet as a the result of a reported cryotherapy session.
Gruden continued to decline comment on anything to do with Brown.
"He's still gathering (information)," Gruden said. "I don't have any information other than that."
Asked if the reports of frostbite were correct, Gruden said, "I'm not going to get into the exact nature of the feet. I'm just not."
The Raiders believe Brown will be back soon, even if they don't know have a timetable. As for Jackson, they'll have to keep their fingers crossed.
Gruden said Jackson got "rolled up a little bit" during a team period. Moments earlier, Jackson had been involved in a minor skirmish with Rams defensive tackle Aaron Donald.
Jackson struggled to stand before he was placed on a cart and driven toward the field house and weight area where he was checked out by trainers. Owner Mark Davis made his way to the restricted area and spent between 10 and 15 minutes there before re-emerging to watch practice.
With Jackson out, Denver Kirkland took reps with the first team at right guard as did Jordan Devey, who is also the Raiders' backup center to Rodney Hudson.
The Raiders are already thin at guard and won't left side starter Richie Incognito on the left side for the first two games of the season as he serves a suspension for violating the NFL's personal conduct policy. Jonathan Cooper was signed as a free agent before camp opened and the plan is to work him in at left guard as the season approaches.
Denzelle Good, considered a potential starter on the left side, had offseason back surgery and is working off to the side with the training staff at an increasing rate of intensity.
If Jackson were lost for a substantial period, it's conceivable the Raiders would be in the market for a veteran guard.
"We're missing Denzelle Good, obviously," Gruden said. "So it'll be a great opportunity for a guy like Denver Kirkland, who's been here for a few years. We brought in Cooper to help at left guard. We'll have to put our heads together, see where we area."
Kirkland, 6-foot-4 and 340 pounds, played in six games with four starts in as an undrafted free agent rookie out of Arkansas in 2016, sat out the entire 2017 season on injured reserve and spent most of last season on the practice squad. He earned a late-season promotion to the 53-man roster and played in two games.
As a rookie, Kirkland did his best work as a blocking tight end in power running formations and played extensively in a 218-yard team rushing performance in a 30-20 win over the Denver Broncos.
Jackson is a third-round pick out of Mississippi State who is considered one of the better guards in the NFL. He started at left guard as a rookie in 2014 and played all 16 games there in 2015 before being moved to the right side after the signing of unrestricted free agent Kelechi Osemele.
The Raiders thought enough of Jackson to sign him to a five-year contract extension in 2017 worth up to $55 million (with $16.5 million guaranteed) to keep him off the free agent market.
"Obviously, Gabe's a great player," linebacker Tahir Whitehead said. "I didn't see what happened and didn't hear about it until after practice. Hopefully he's OK and we'll just go from there."
