Christopher Ryan Helmer, a 16-year-old Roseville boy who suffered major injuries in a July 28 traffic collision, has died, Roseville police reported Monday.

Helmer succumbed to his injuries Sunday.

A Woodcreek High School student athlete, Helmer was described by those who knew him as a well-liked, friendly and respectful young man who showed great promise, especially on the athletic field. He played junior varsity football last year and was anticipating playing for the varsity team until the accident put those plans on hold this summer.

“He was a great kid who understood his role and worked hard to get better every day,” said Kelly Mayo, a Woodcreek junior varsity football coach. “He had some really neat tools. The kid could run and the kid could jump. He left us all way too soon.”

Woodcreek Principal Jess Borjon said Monday students had been informed of their classmate’s death and counselors were being made available for those who requested them.

On his MySpace page, which was filled Monday with messages of sympathy and last respects, Helmer had written under “interests” a typical teenager’s preoccupations – football, baseball, music and “chillin.”

Kyle Mahnke, 16, did a lot of the latter with his longtime friend. Helmer enjoyed playing sports, practicing the drums, flirting with girls and watching TV – especially mixed martial arts, said Mahnke, also a junior at Woodcreek.

“He loved watching it, talking about it, having arguments about it,” Mahnke said of the sport. “He was a good kid; he just liked to have fun, hang out, make jokes.”

Helmer was riding in the backseat of a 1992 Honda Accord shortly before midnight July 28 when the car was broadsided near the Galleria mall.

Police say the Honda’s driver, a 17-year-old Citrus Heights girl, was turning left onto westbound Roseville Parkway from northbound Galleria Boulevard shortly before midnight when the car was struck by a 1995 full-size Chevy pickup traveling southbound on Galleria.

The Honda’s driver and another passenger in the car, a 16-year-old Roseville girl, suffered minor injuries. The pickup’s driver, Jose Luis Serrano-Diaz of Roseville, was also injured.

Police said they have not determined which driver was at fault. Neither driver was found to be under the influence of alcohol or drugs and all parties were wearing seatbelts. An investigation is ongoing.

Helmer remained in a coma ever since the crash, a family friend said.

“He was getting better, breathing on his own,” Mahnke said. “He got moved back to his house. Then he passed.”

Before the collision, Helmer had been planning a trip to Southern California with friends. He was also going to check out San Diego State University, which he was considering attending.

At Woodcreek, Helmer’s absence on the football field has been acutely felt by his comrades, who have been wearing patches in his honor, Mayo said.

“Chris Helmer will always be on our team,” he said.

A memorial service was scheduled for 11 a.m. Saturday at Adventure Christian Church, 6401 Stanford Ranch Road, Roseville.