SANTA CLARA, Calif. -- San Francisco 49ers linebacker Ray-Ray Armstrong didn't have even a full two-game sample size to make an impression on coach Chip Kelly and his staff. What Armstrong showed, plus what he'd done previously, was apparently enough to land him a two-year contract extension with the team earlier this week.

"Ray-Ray had a strong offseason and was off to a good start in 2016 prior to being sidelined for the season due to injury," general manager Trent Baalke said in a statement. "He has continued to work hard in his rehab and is a young player with a bright future in front of him. We look forward to his continued development and contributions, both on and off the field."

When the Niners trained in Orlando between games against the Dolphins and Bears last month, defensive coordinator Jim O'Neil expressed interest in bringing Armstrong back despite the small sample size. O'Neil stepped to the podium for his weekly news conference Tuesday and started by calling Armstrong's contract extension "awesome," saying Armstrong is an example of someone who worked his way from undrafted free agent to a player the team values enough to sign before he reached free agency.

“Well, we did our evaluations at the end of training camp and I think that everybody knew how I felt about him," O'Neil said. "You guys asked me about him when we were down in Orlando and I don’t think it was a secret that I was pretty high on him. I think that when you look at what we want to be defensively and what we are, I think he’s a really good fit.”

After taking part in a three-way competition for the starting inside linebacker job during training camp, Armstrong had been sharing snaps in his first game and a half. Then he suffered a season-ending pectoral injury in Week 2 against Carolina, landing him on injured reserve and cutting his season short.

In last week's game against Atlanta, the Niners lost Nick Bellore to an elbow injury and were so thin at inside linebacker that they had to use safeties Vinnie Sunseri and Antoine Bethea there at various times. The timing of Armstrong's extension is likely a coincidence, but it shouldn't be a surprise that the team moved to re-sign an inside linebacker only a day after having to dig into the secondary to have enough bodies to play.

“I do think that that’s the way it was going for him," O'Neil said. "I do see him as that type of player. He’s got a skill set that’s very different than anything we have in that room as far as his ability to blitz and play man coverage, which is what we want to be defensively.”

Before the injury, Armstrong had eight tackles, an interception and a fumble recovery. The injury was a particularly damaging blow for Armstrong because he entered the league as an undrafted free agent and spent his first few seasons bouncing between the Rams, the Raiders and Niners in a limited role on special teams.

As a converted safety, Armstrong looked to be a player who could help in coverage but come off the field on running downs. But O'Neil and the Niners believe he is capable of playing all three downs.

“I think that was one of the things that if you asked any of the personnel guys and any of the coaches, that was our biggest question mark and I thought that he answered that throughout the preseason," O'Neil said. "He really showed up in the crossover practices against Denver and Houston, where we got a lot of two-back stuff where they were downhill and he went to go get it and it showed up in some of the preseason game stuff.”