Researchers studying a degenerative disease in former athletes say 11 of 12 brains of deceased former NFL players tested over the past year showed signs of chronic traumatic encephalopathy, or CTE, continuing a trend they’ve been tracking.

A story posted on PBS.org on Friday reported that a total of 87 of the 91 brains of former NFL players examined in recent years by researchers with the Department of Veterans Affairs and Boston University have had CTE.

According to PBS, many players whose brains were donated for research suspected they had CTE, which therefore skews the population of brains being examined.

Gina DiGravio-Wilczewski, media relations manager at the Boston University School of Medicine, provided the figures for the past year of research.

Linked to repeated brain trauma, CTE is associated with symptoms such as memory loss, impaired judgment, depression and, eventually, progressive dementia.

NFL spokesman Brian McCarthy wrote, in part: “We all know more about this issue than we did 10 or 20 years ago and will continue to learn as more research is conducted and discussed by the medical community. But we are not waiting to make the game and players safer. We have been and will continue to make improvements.”

Ann McKee, chief of neuropathology at the VA Boston Healthcare System, told PBS: “People think that we’re blowing this out of proportion, that this is a very rare disease and that we’re sensationalizing it. My response is that, where I sit, this is a very real disease.”

Manziel to start

Cleveland quarterback Johnny Manziel will start Sunday in the home opener against the Tennessee Titans because starter Josh McCown has yet to be medically cleared to return from a concussion, the team announced Friday.

McCown met with an independent neurologist Friday morning but was not cleared to practice. McCown, who’s 17-33 as an NFL starter, remains in the league’s concussion protocol and has officially been ruled out for Sunday.

On Thursday, Browns coach Mike Pettine said he couldn’t envision sitting McCown against the Titans if the veteran were cleared in time to fully participate in Friday’s session.

But with McCown out, Sunday’s game between the Browns (0-1) and Titans (1-0) will feature a matchup of former Heisman Trophy-winning quarterbacks.

Manziel received the honor in 2012 at Texas A&M, and Titans rookie Marcus Mariota won it last year at Oregon. Mariota is coming to town after throwing four touchdown passes and posting a perfect rating of 158.3 in his regular-season NFL debut.

It will be Manziel’s first start since last year, when he went 0-2 during a disastrous rookie season.

Now he’s seeking redemption.

“I’m just trying to go out and play better football than I have in the past,” Manziel said Wednesday. “I’ve been disappointed in the way I’ve performed, especially ending the season last year. It didn’t end on a very good note.”

Etc.

• Bears receiver Alshon Jeffery (hamstring, strained left calf) and outside linebacker Pernell McPhee (knee, wrist) did not practice Friday. Both suffered new injuries late this week.

• Green Bay will be without veteran right tackle Bryan Bulaga for its home opener against Seattle.

Bulaga injured his left knee in practice on Thursday. The setback comes a year after the sixth-year pro suffered an injury to the same knee in the Packers’ season-opening loss at Seattle. Bulaga at that time missed only one game with a sprained MCL.

• Injured Tampa Bay receiver Mike Evans hopes to return to the lineup Sunday against NFC South rival New Orleans.

The second-year pro who’s one of Jameis Winston’s top targets has been sidelined since the middle of August because of a sore right hamstring. He sat out the Buccaneers’ 42-14 season-opening loss to Tennessee but practiced on a limited basis for the third straight day Friday and is listed as questionable to play against the Saints.

• Lions tight end Brandon Pettigrew was ruled out for Sunday’s game at Minnesota because of a hamstring injury.

• Bills running back LeSean McCoy is questionable for Sunday’s game against the Patriots because of a hamstring injury.

• Falcons receiver Julio Jones says he’ll be ready to go Sunday against the Giants after sitting out two practices because of a sore hamstring.

• The Cowboys discussed putting receiver Dez Bryant on the injured/return list but decided against it. Placing the Pro Bowl receiver on that list would have forced him to miss a minimum of eight games. Club officials are hopeful that Bryant, who underwent surgery to repair a broken fifth metatarsal in his right foot on Monday, will be able to return sooner although there are no assurances.

• Redskins tight end Jordan Reed is considered questionable for Sunday’s game against the Rams because of a bothersome leg muscle.