Bringing noteworthiness to an otherwise insignificant exhibition, the Oakland Raiders’ preseason debut Friday night against the Detroit Lions will officially mark the beginning of the franchise’s second Jon Gruden Era. Gruden coached in the Bay Area from 1998 to 2001, and he remains the franchise’s top coach by winning percentage since Tom Flores left the team in the late 1980s. The Raiders are desperate for Gruden to replicate that success for them now, so much so that they lured him away from his gig at ESPN with a bewildering 10-year, $100 million contract in January.

Gruden’s track record speaks for itself, with the 44th-most wins of any coach in pro football history. But it also bears mentioning that Gruden hasn’t roamed an NFL sideline in almost 10 years, since being fired by the Tampa Bay Buccaneers after the 2008 season. He spent most of the intervening years broadcasting, and the time away might be the biggest obstacle to Gruden restoring Oakland to glory. Across multiple sports, history tells us that coaches who return to the game after a decade away are usually unable to improve upon their records from before they left.

By coming back to the NFL 10 years after his last season, Gruden joins a pretty peculiar group of do-over coaches. It isn’t as though these kinds of coaches are sitting around doing nothing during their years off — in addition to broadcasting like Gruden, many serve as high-level assistant coaches after their first head-coaching stints — but it’s still rare to get another shot at the big chair after so much time away. Here’s the full list of NFL, NBA and MLB coaches/managers since 1977 (the year after the NBA-ABA merger) who had a gap of at least 10 years in their coaching resumes, along with how they did in their first season back relative to their previous career:

Coaching returns like Jon Gruden’s usually fall flat Change in win percentage from previous career mark for coaches who returned to the NFL, NBA or MLB after at least 10 years away, 1977-2018 Prev. Career Gap Return Season Coach Sport WPct Years Year Team WPct Change in WPct J. Gruden NFL .540 10 2018 OAK ? ? J. Pardee NFL .489 10 1990 HOU .563 +.074 T. Marchibroda NFL .554 13 1992 IND .563 +.009 P. Carroll NFL .516 11 2010 SEA .438 -.078 D. Vermeil NFL .535 15 1997 STL .313 -.222 J. Gibbs NFL .674 12 2004 WAS .375 -.299 C. Gailey NFL .563 11 2010 BUF .250 -.313 A. Shell NFL .587 12 2006 OAK .125 -.462 P. Silas NBA .317 16 1999 CHH .629 +.312 H. Brown NBA .484 16 2003 MEM .378 -.106 B. Russell NBA .565 11 1988 SAC .293 -.272 J. McKeon MLB .480 10 1988 SD .583 +.103 F. Robinson MLB .475 11 2002 MON .512 +.037 R. Miller MLB .456 12 1998 BAL .488 +.032 T. Collins MLB .506 12 2011 NYM .475 -.031 B. Valentine MLB .510 10 2012 BOS .426 -.084 Average -.087 Among coaches who spent at least two years as a team’s primary coach (coaching at least half a season’s games) before leaving the league. Source: Sports-Reference.com

In the past four-plus decades, only 15 other coaches have even tried what Gruden is attempting — and their success rate has been spotty at best. In their first seasons back, this group of returning coaches saw an average drop in winning percentage of about 90 points, compared with their career marks before their long layoffs. Only a third managed a winning record in their return season, and 20 percent only lasted one season before retiring (or being fired) again for good.

Not that there aren’t any success stories in the bunch. Dick Vermeil and Pete Carroll both recovered from mediocre starts to visit three total Super Bowls in their next NFL acts, winning two titles. (Carroll, it should be said, had also established himself as a very successful college coach during his time away from the NFL.) Terry Collins weathered the Mets’ Madoff crisis to put in six seasons with the club, guiding it to the World Series in 2015, while Paul Silas coached three separate franchises over nine seasons upon his return to the NBA. And Jack McKeon — who was 57 when he returned to managing with the 1988 Padres after a 10-year absence — stuck around for parts of 10 MLB campaigns over the next 17 years, winning the 2003 World Series with the Florida Marlins. After initially re-retiring in 2005, McKeon returned to the Marlins again in 2011, at age 80, for 90 games before finally hanging up the uniform for good.

But more frequently, these Gruden-esque returns have failed to recapture the glories of the initial run. (The Raiders know about these declines firsthand: Art Shell’s coaching stint in Oakland went from a success in the early 1990s to a total disaster after he returned to the club in 2006.) Among our group of coaches above, fewer than half had a better winning percentage in Round 2 than they had the first time around, with the average coach winning at a percentage 65 points lower over the remainder of his career than he’d done before his long absence.

For Gruden, such a dip would take his record just below .500 — and while that wouldn’t be terrible by recent Raiders standards, it’s also not what the team was envisioning when it signed that $100 million deal, with a franchise relocation looming on the horizon as well. Of course, there are some reasons to think Gruden can do better than his peers from the returning-after-a-decade-away club. Quarterback Derek Carr is in his prime and should have more weapons to work with in the form of newly acquired receivers Jordy Nelson and Martavis Bryant (plus two-time 1,400-yard rusher Doug Martin). A defense that ranked among the worst in football last season has a completely overhauled linebacking corps around star edge-rusher Khalil Mack. Overall, enough of the roster that won 12 games two years ago remains that a bid for the AFC West crown wouldn’t be totally crazy in Gruden’s first year back.

Even so, the Raiders deserved every bit of their 6-10 record last year, and they did it with better-than-average injury luck. Meanwhile, Gruden didn’t exactly spend the offseason assuaging concerns that his thinking was stuck in the early-2000s era during which he’d been most successful. And maybe that’s the biggest reason that some of these coaching retreads end up going flat: The game evolves much faster than those on the outside can imagine, even if they’re observing it from the announcing booth. Tactics and ideas that worked a decade ago are now passé, and you might not know it until the games begin.

Gruden will get his very first taste of that Friday night, and we’ll begin to see whether the time away sharpened his focus or simply left him out of touch with the modern game.