U.S. midfielder Jermaine Jones, who suffered a head injury during Friday’s World Cup qualifier in Jamaica, did not practice Sunday and is scheduled to see a neurologist Monday. Although U.S. Soccer Federation officials have not officially ruled him out of Tuesday’s match against Panama here in Seattle, Jones tweeted: “I’m out for the game against panama”.

The medical staff is using standard concussion protocol to determine the extent of Jones’s injury and how soon he could resume training. He rode a stationary bike Sunday.

After Tuesday’s match, the Americans will begin preparing for next week’s qualifier against Honduras at Rio Tinto Stadium in Sandy, Utah.

Geoff Cameron, a backline player who replaced Jones in the 59th minute of the 2-1 victory in Kingston, is the top candidate to start alongside Michael Bradley at CenturyLink Field.

“I don’t know at the moment what Juergen [Klinsmann] is thinking,” goalkeeper Tim Howard said, “but [Cameron] did seem comfortable playing that position [Friday]. He played it in Houston [in MLS]. It feels natural to him. He runs really easily. He has good physical stature. Yeah, he would make a good partnership. But we also have options in there,” citing Sacha Kljestan.

*USSF officials say ticket sales remain around 35,000. The Sounders, the runaway attendance leaders in MLS every year, drew 53,000 on Saturday night. Ticket prices are higher for the qualifier — as they should be: It’s a high-profile match. The cost of installing natural grass over the artificial turf increased the expense of staging a game in Seattle, as well. Higher production costs meant higher ticket prices. I’ll address Seattle hosting a qualifier — it’s a good thing, despite the wrinkles — in Tuesday’s print editions.

I asked Sounders Coach Sigi Schmid about the prolonged effort to stage a big match in the Pacific Northwest. He couldn’t resist taking a fun little dig at the USSF installing grass over turf at other stadiums over the years.

“Obviously there is never an issue of laying grass at Gillette [Stadium in Foxborough, Mass.]. That usually happens without a problem,” he said with a laugh.

With a serious tone, he added: “Laying grass, it’s never an ideal situation. I can understand that. But I think it’s great they’ve come to the Northwest. I know I am supposed to be a Portland hater, but certainly Portland’s atmosphere is unique as well. Smaller stadium, a little more intimate. This will be different because you are going to get more people in here. But it’s something our fans in this part of the country deserve.”

The U.S. squad tested the grass for the first time late in the day Sunday. Media availability was conducted before the training session, so reaction to the surface will have to wait until Monday.

*Panamanian star forward Blas Perez (FC Dallas) has been ruled out of Tuesday’s match because of gastroenteritis, his federation announced. He played 70 minutes against Mexico on Friday in Panama City but was apparently feeling the effects of the stomach problems.

*Sounders forward Eddie Johnson threw out the first pitch at the Mariners-Yankees game this afternoon at Safeco Field. Howard and Clint Dempsey flanked him at the mound. The toss wasn’t bad — for a soccer player or otherwise.

“I think it would have been a ball, but he didn’t bounce it in,” Howard said. “I knew he was nervous. I was nervous for him. I told him to make sure he got it in there.”

The players stayed a few innings before rejoining the team ahead of training next door at CenturyLink.