Rex Ryan's second season in Buffalo is already off to a shaky start, even before the season truly begins. Since Ryan's underwhelming first year ended without a playoff berth, he's been forced to deal with a myriad of injuries.

Star receiver Sammy Watkins broke his foot. First-round pass-rusher Shaq Lawson underwent shoulder surgery. Both are expected to suit up for the regular season at some point. The latest injured member of the Bills roster, however, is facing a significantly longer timeline to return.

As first reported by ESPN's Adam Schefter and confirmed by the Bills on Wednesday, second-round linebacker Reggie Ragland of Alabama lost his rookie season due to a torn ACL.

ESPN's Mike Rodak witnessed the injury and provided a play-by-play:

As the fourth-year GM and Bills owner Terry Pegula sat in a golf cart on the sideline during 11-on-11 drills, Ragland chased running back Reggie Bush in their direction, only to pull up limping and immediately go to the ground.

Center Eric Wood was among the first to trot over and check on Ragland, who laid with his back on the turf. The second-round rookie quickly told his veteran teammate that he had hurt "my knee, my knee" -- chilling words that were surely within earshot of Whaley and Pegula.

So, clearly, this is a costly injury. For one, the Bills traded up to draft Ragland with the 41st overall selection, forking over their own second-round pick and a pair of fourth-rounders. At the time, the move was justified by Ragland's ability to play immediately.

As CBS Sports' and NFL Draft Scout's Rob Rang wrote after the draft, "Ragland is a plug-and-play option in Buffalo's defense, offering a similar blend of instincts, power and reliable tackling comparable to longtime Jets' standout David Harris, a favorite of Ryan's back in New York."

So, not only is this injury costly in terms of the value the team lost when it traded up, it's also costly in terms of what the Bills will actually be missing on the field.

Rang continued:

Like Harris (as well as former Jets and Baltimore Ravens standout Bart Scott), Ragland is the perfect inside linebacker for Ryan's scheme. While perhaps not an elite athlete, he is agile and accelerates quickly for 6-foot-1, 247 pounds. Ragland locates the ball quickly, he is hyper-aggressive in taking on and shedding blocks in the hole, and he is an intimidating presence as a hitter. Further, while alert enough to handle occasional coverage duties, he is better defending the pass by rushing -- either on the blitz or dropping his hand to the dirt and rushing out of the three-point stance.

On Wednesday, Ryan tried to speak highly of the team's depth, saying "guys will step up." The guy might end up being Zach Brown, who's listed behind Ragland on the team's latest depth chart. Brown signed a one-year deal with the team this offseason, before the team drafted Ragland. So, not too long ago, Brown projected to serve as a starter -- or, at the very least, compete for the role.

When speaking about him earlier this week, Ryan highlighted Brown's coverage skills, but also pointed out his inefficiencies.

"Zach's an unusual guy. I mean, he's a talented guy, obviously, that can really run and he's got excellent cover skills," Ryan said, per The Buffalo News. "That's the thing that jumps out at you. You know, I'd like to see him get a little dirtier on the goal line and stuff like that, but he is a real talented kid.

"He's had starting experience in the league and he can do a lot of things man-coverage wise, different things like that. So he's a guy that, you know, we feel good about, we feel fortunate that we have him."

That matches what Pro Football Focus wrote when Brown entered free agency, when they named him one of the six best free-agent bargains:

While Brown struggles a little to shed blocks, he's a reliable tackler and has the quickness and athleticism to stick with backs and tight ends in coverage. In 2015, he allowed just 22 receptions on 31 targets for 198 yards, no touchdowns, two interceptions, and a pass defense. The 61.0 QB rating he allowed was bettered by only Josh Mauga and Luke Kuechly. Couple Brown's contributions in the passing game with a top-10 tackle efficiency -- he missed just 5-of-77 attempted takedowns last year -- and his appeal to NFL evaluators should be obvious.

In four seasons with the Titans, Brown played in 49 games (33 starts), recording 260 tackles, 10 sacks, and six picks. Yet Ryan and defensive coordinator Dennis Thurman both seemed unsure Wednesday if Brown can function as an every-down linebacker.

So, just to be clear, a Bills' draft that was initially thought to have produced two day-one starters in Lawson and Ragland, is now down to just Lawson, who is still several weeks away from practicing, as ESPN reported. And keep in mind, his replacement, Manny Lawson, tore his pectoral muscle while lifting weights last month. So, that means Geno Smith's puncher, IK Enemkpali, might actually see meaningful minutes.

The point being, the improvements Ryan's defense underwent this offseason are slowly being wiped away. Rather, the upgrades Ryan made to his 19th-ranked defense don't even look like upgrades at this point. They look like non factors, for now at least.

So no, Ryan's declaration in June that the Bills won the offseason definitely isn't holding up. But hey, at least Ryan hired his brother to fix his defense and ride bicycles together.