SANTA CLARA -- Linebacker NaVorro Bowman has started running and appears to be on track to return for the 2017 regular season.

Bowman sustained a season-ending torn left Achilles in the 49ers’ Week 4 loss to the Dallas Cowboys. With Bowman sidelined for much of the season, the 49ers’ defense was the worst in franchise history.

The 49ers’ last-ranked defense surrendered more total yards (6,502), points (480) and rushing yards (2,654) than any team in franchise history. The 49ers' season concluded Sunday with a 25-23 loss to the Seattle Seahawks.

The 49ers finished with a 2-14 record, leading CEO Jed York to fire general manager Trent Baalke and coach Chip Kelly.

“It’s been tough because I started off with these guys,” Bowman said. “For me to go down and for things to continue to go down and not pick up, it’s been tough for me to watch.

“Part of that is, I put that on me, because guys look at me as a person to handle certain things and get us on the right pace out there. Hopefully we’re going get out of this slump and get back to 49er football.”

Bowman said he has started running in the pool, but his rehabilitation has not moved on to flat ground. He still has a long road of rehab ahead of him to get cleared for a return to football activity.

“I’ve been sitting back watching everything,” he said. “We definitely have talent. You can see throughout the game that the guys are still playing hard, playing for one another. That’s what you found as a foundation for a team, guys to give 100-percent effort.”