We've seen many times when an injury can rob a player's production and it often, for all intents and purposes, ends a career.
Michael Sinclair didn't get injured, he got robbed by an illness—diabetes—that manifested at the peak of his NFL career and he was never the same after.
In 1991 the Seattle Seahawks drafted Sinclair in the 6th round of the draft. He'd been the best defensive lineman in the Lone Star Conference in 1990 playing for Eastern New Mexico University. He'd been All-LSC both as a junior and senior and ended his years as a Greyhound with 279 tackles and 30 sacks.
Sinclair's hopes of playing pro ball rested on his ability to gain some weight. He was 238 pounds at ENMU and that was not going to cut in in the NFL so we went to work. Even though he had very good speed (4.58 in the forty) he was still a long shot to make the team.
Prior to his rookie season, he was able to gain twelve pounds to get up to 250 pounds and had a good camp and preseason—catching the coaches' eyes. He didn't quite make the club but was on the Seahawks practice squad and was activated and on the roster for the final four games but he never played in a game.
However, he'd shown enough promise that he was assigned to the NFL's new development league—the WLAF (that was renamed NFL Europe several years later)—and in the Spring of 1992, he played for the Sacramento Surge and was a major cog on a team that won the league championship.
Sinclair caught a break there due to the fact one of the Surge front office executives was former Ram great Jack Youngblood who'd often attend practice and offer tips to young linemen. In fact another of those young linemen was Bill Goldberg, who was a defensive tackle on the club.
It seems Goldberg would turn most reps into wrestling matches with offensive linemen and he would get off the block, just playing into the guard's hands. Youngblood once said, "Bill, I know you can whip him but what I want to see is if you can get off his block."
With the Surge Sinclair improved his craft and totaled ten sacks in ten games and was a league All-Star and was back with the Seahawks for the 1992 season.
That year long-time veteran left defensive end Jacob Green had been released and right end Jeff Bryant was moved to left side. The plan was for him to play in the base defense with Sinclair coming in on passing downs but it didn't materialize until a month into the season due to a severely sprained ankle that slowed him. When he was healthy, though, Sinclair didn't impress. He was "Thinking too much" and that still on the light side, weighing 258 pounds despite two years of hitting the weights.
Things finally came together in 1993 with Sinclair excelling in his role as a nickel rusher. That off-season, he stayed a dedicated weight lifter and ate healthily and that paid off in a big way. He built himself up to 271 pounds and retained his quickness and get-off.
He told the media, "This is the first year I will be able to play a full season."
There was talk among the coaches that he might be ready to be the starting left end but by the start of the season the 1992 plan was back: Bryant on run downs and Sinclair would play in nickel defenses (with Michael McCrary on the opposite side).
After eight games he was third in the AFC in sacks . . . then he broke his thumb and it kept him out the rest of the season. He had shown such promise and then boom, he was out and didn't make it through the full season as he'd hoped.
He didn't get that full season in 1994 either. He once again continued his weight program and weight gain, tipping the scales at around 290 pounds but he was slowed by a knee injury and then a groin injury and was never fully recovered until late November. Sinclair ended the season strong but again it was another disappointing year.
Dennis Erickson brought change to the Pacific Northwest team in 1995. He brought in Greg McMackin to run the defense. McMackin had been a long-time college coach and in 1993-94 was the defensive coordinator for the Miami Hurricanes and brought with him a defensive scheme that called for a get-up-the-field philosophy for the defensive line.
While it did not fully manifest that first year the change was well suited for Sinclair and his to-be partner in crime McCrary.
Erickson, on his arrival, told Sinclair to drop his weight telling him that 290 pounds was too much and also to not use his bull rush as much. He was to get up the field, putting his best asset, his quickness, to fuller use without trying to push a tackle back to the quarterback.
Sinclair was finally a starter and played his first full season Seattle improved from 6-10 to 8-8 and good things seemed like they were on the horizon for Sinclair.
Indeed they were.
In 1996 the new scheme paid off, big time. With four dynamic players, the defensive line ranked among the best in the NFL. Sinclair (now down to 267 pounds) and McCrary were the ends with powerful Cortez Kennedy and super-quick Sam Adams inside at the tackle spots. They sacked opposing quarterbacks 48 times, the most since 1985. Sinclair and McCrary combined for 26.5 and countless pressures.
Sinclair had arrived . . . he'd become the player he'd worked to be and was rewarded with being voted to his first Pro Bowl.
The Seahawks lost McCrary to free agency in 1997 but Sinclair rolled on recording 12 sacks and forcing 5 fumbles and was voted to his second consecutive Pro Bowl.
Going into 1998 Sinclair was underpaid according to Seattle columnists and he considered holding out but decided against it. He told the media that honoring the contract he signed was more important and that the money would take care of itself in due time.
Again, he had a stellar season. He led the NFL in sacks and forced fumbles, was Second-team All-Pro and made his third Pro Bowl.
He was on a hot streak. From 1996-98 no one, not Bruce Smith, not Reggie White, not Kevin Greene, or any other dominant rusher had more sacks than Sinclair's 41.5 sacks and though it was not known at the time, through the magic of Pro Football Reference's Stathead now it is clear that no one forced more fumbles in that span either.
Though not a household name, Sinclair was among the elites at his position and was doing things as well as the best of the best. His dedication paid off.
And the money came.
In August of 1999, Sinclair signed a seven-year $35 million contract that kept him signed through 2005. The Seahawks voided the last two years of a four-year deal he signed in 1996 so, in effect, it was a five-year extension and it made him one of the NFL's highest-paid defensive linemen.
Then the unexplained tiredness came. The inability to keep weight on. Seeking answers Sinclair was tested and found to have Type-II diabetes. He knew with treatment it could be controlled but still, he was in an industry where slowing by a half-step could take away his ability to compete.
With that and with Mike Holmgren's desire that his defensive ends focus more on stopping the run it seemed 2000 was going to be a challenge. Defensive coordinator Jim Lind brought his defensive ends "in". Rather than being split outside in a "wide 9" technique. Sinclair had to play tighter, on the outside shoulder of the tackle, at 5-technique. That cut the angles he had to take to the quarterback if the opposing offense decided to pass from a running formation or on a likely run down.
Sinclair was third on the club in sacks with six and though he did force four fumbles it was clear that Sinclair was playing up to the level he had in the previous few seasons.
He got a reprieve the next year with, once again, a new defensive coordinator, Steve Sidwell. Sinclair was allowed to spit out wide again, something he thought was better for his skill set. He proclaimed to the media, "The new scheme put me back to playing outside." He added that his diabetes was "stabilized".
But all that didn't pan out.
Sinclair's final two seasons in Seattle were dismal by his standards and that led to him being released early in 2002. He was looking for a job and to bolster his opportunities he got his weight up to 277, the most since 1994. He visited the Rams but signed with the Broncos for $750,000 but failed to make the club. A short time later, when injuries hit the Philadelphia Eagles defensive line, Sinclair was signed to provide some temporary depth. His stint there lasted just four games.
When diabetes manifested Sinclair was just 31 years old. He'd been among the best at his position for a few seasons. And though there was a hiccup in the 1999 defensive scheme that did not play to his strengths, it was the illness that sapped him of his elite ability and made him ordinary. He only got to play a short time under his big-money contract.
He's still the second-leading sacker in Seahawks history (behind only Jacob Green) and his 16.5 sacks in one season are still the franchise record. His three Pro Bowls as a defensive end are tied for the most in term annals—though Jacob Green, who had just two, likely deserved more.
He went on to coaching. He had a stint in NFL Europa and then six years in the CFL and one season in the NFL, in 2013 with the Chicago Bears.