Unbeknownst to them, their seasons turned at the same time.
The Sharks went 32-16-5 in their last 53 games. Joe Thornton had 66 points and finished with 82.
The Penguins went 33-16-5 in their last 54 games under Sullivan. Sidney Crosby had 66 points and finished with 85.
Now they are getting ready to play in the Stanley Cup Final. Here are 10 storylines to follow in a series featuring two teams that traveled similar paths to the biggest stage in hockey:
1. CROSBY GUNNING FOR MARIO'S MARK
Mario Lemieux won the Stanley Cup with the Penguins in 1991 and 1992. Crosby has a chance to match what Super Mario did in Pittsburgh.
If Crosby wants to pose alongside Lemieux in Pittsburgh lore, he has to win the Stanley Cup again. Crosby won it in 2009 in a Game 7 victory against the Detroit Red Wings.
No matter what Crosby does, he will be a leading storyline throughout the Final. He is in every series and every game, only now the spotlight is brighter and the world is watching to see if Sid the Kid can match Le Magnifique.
Video: Dan Rosen on the legacy of Sidney Crosby
2. JUMBO, PATTY FINALLY ARRIVE
It's not rare anymore to see the captain of the winning team in the Stanley Cup Final accept the trophy from Commissioner Gary Bettman, skate around with it and find the oldest or longest-tenured player on the team who hasn't won the Cup and hand it to him next.
Thornton and Patrick Marleau might have to fight for the handoff from Joe Pavelski if the Sharks win the Cup.
Marleau, the longest-tenured Sharks player, and Thornton, the second-longest, are in the Stanley Cup Final for the first time despite combining to play 3,093 combined regular-season and playoff games, including 2,526 with the Sharks.
Marleau has played 1,576 total games in his 18 seasons with San Jose. He never has played a game for another NHL team. Jumbo Joe has played 950 total games with the Sharks and 1,517 in his 18-season NHL career.
3. A MEATY LINE
They're called the "HBK Line," and they even have their own sandwich at Pittsburgh's famous Primanti Bros.
Carl Hagelin, Nick Bonino and Phil Kessel have been the Penguins' best line in the Stanley Cup Playoffs so far, combining for 17 goals and 45 points. Kessel arguably is the Penguins' leading candidate to win the Conn Smythe Trophy with team-highs of nine goals and 18 points.
The success of the line, and the nickname, given to them by a Pittsburgh-area radio show host, has turned them into a phenomenon. How do we know? Primanti Bros. doesn't make a sandwich for just anybody. They did it for the "HBK Line" and it's called the HBK sandwich. It's loaded with ham, bacon and kielbasa. It also has Primanti Bros. famous dry coleslaw and french fries tucked between two slices of white bread.
4. REVERSE THE CURSE
For the fans in San Jose who think their hockey team is cursed, how do you think they felt when they saw a black cat run onto the ice before Game 1 of the second round against the Nashville Predators?
That sort of thing can legitimize a fan's superstitious view on his or her sports team being cursed. Ask Chicago Cubs fans how they feel about the black cat that ran onto the field at Shea Stadium during a 1969 game against the New York Mets that led to the Cubs' collapse that season.
Yet here are the Sharks in the Stanley Cup Final, in the process of reversing their own curse and that of the black cat all at once.
Instead of being cursed, they've embraced the cat, a female named Jo Paw-velski. They delivered it to the Humane Society of Silicon Valley and gave her a Twitter feed. All of that led to her being adopted.
Now the Sharks, who have started traveling with a stuffed black cat, are four wins from a championship. Maybe it's because of the black cat instead of in spite of her. Can superstitious sports fans even consider that without their minds blowing?
Video: Previewing the 2016 Stanley Cup Final
5. PITTSBURGH'S NEWEST HOCKEY FAN
The "HBK" phenomenon in Pittsburgh also brought the original "HBK" into the hockey world as a Penguins fan.
Shawn Michaels, a former pro wrestler who went by the nickname the "Heartbreak Kid," was given a king's welcome to Pittsburgh before Game 5 against the Lightning. He watched the game from seats four rows off the glass, next to former Pittsburgh Steelers defensive end Brett Keisel. Michaels wore a jersey with the initials "HBK" and the number 156 on the back, the sum of the numbers of Hagelin (62), Bonino (13) and Kessel (81).
Michaels met Lemieux and was shown on the scoreboard multiple times, including once when he flexed to show his massive biceps.
But the Penguins lost, so when it came time for Game 7 at Consol Energy Center, Michaels tweeted that he'd be watching from afar because he didn't want to jinx his new favorite team. They won, so maybe he won't be back.
6. METALLICA AND MACGYVER MANIA
The "Shark Tank" again could be teeming with celebrity fans who could help the home team rig up a game plan for a seek-and-destroy mission in the Cup Final.
Oh yeah, we're talking about Metallica ("Seek and Destroy") front man James Hetfield and the man who could rig up anything with a string, two pingpong balls and a flashlight, MacGyver himself, actor Richard Dean Anderson.
Each was at Game 6 of the Western Conference Final on Wednesday and proved to be good luck charms in San Jose's 5-2 win against the St. Louis Blues.
7. SULLIVAN'S FULL-CIRCLE JOURNEY
This is Sullivan's first trip to the Stanley Cup Final after 26 years in professional hockey as a player and coach. The irony is he's facing the team that gave him his first chance in the NHL.
Sullivan played 64 games as a rookie for the Sharks in 1991-92, their inaugural season. He played 81 games with San Jose in 1992-93 and 26 in 1993-94 before being traded to the Calgary Flames.
There was no way he could envision San Jose becoming the hockey town it has become back when he was playing in the Cow Palace for an expansion team filled with NHL journeymen and former minor leaguers. Now it's his job to keep the Sharks from becoming Stanley Cup champions.
Video: DeBoer, Hitchcock mic'd up for WCF Game 6 duel
8. BEARD WATCH
The beards being worn by Thornton and Sharks defenseman Brent Burns have become characters in the playoffs. They kind of resemble the players themselves.
Thornton's beard is long, graying, a bit jungle-like but still somewhat in control, like he is with the puck. Burns' beard is wild, jagged, untamed, aggressive and fun, just like he is on and off the ice.
These beards will be talked about a lot in the Stanley Cup Final. They have reached legendary status in terms of playoff beards, even if Thornton cheated and started growing his in December.
9. MURRAY'S NET NOW
Penguins rookie goalie Matt Murray, who turned 22 on Wednesday, won Games 6 and 7 against the Lightning after sitting on the bench while veteran Marc-Andre Fleury, their longtime No. 1 goalie, got a crack at earning his job back in Game 5.
Fleury faltered. Murray made 44 saves on 47 shots to win the last two games of the series. He enters the Stanley Cup Final with 11 wins, a .924 save percentage and 2.22 goals-against average in 15 starts.
Murray now has more experience and wins in the NHL playoffs (15 games, 11 wins) than he does in the regular season (13 games, nine wins). He is the third goalie in the expansion era (since 1967) to reach double-digits in postseason wins before hitting the mark in the regular season. The others are Ken Dryden (1971) and Mike Vernon (1986), according to the Elias Sports Bureau.
Video: TBL@PIT, Gm7: Murray denies Stamkos' slap shot
10. FORMER DEVILS BACK FOUR YEARS LATER
Sharks coach Peter DeBoer, forward Dainius Zubrus and goalie coach Johan Hedberg reached the Final four years ago with the New Jersey Devils. DeBoer was the coach, Zubrus was an important, versatile forward, and Hedberg was the backup goalie.
Their memories of that run might be sweet, but their lasting memory is bitter after they lost in six games to the Los Angeles Kings.
This is the first time any of them have returned to the playoffs since that run.