Thomas Stripling went to Spring Training with the Dodgers not completely confident he'd make the club. He'd started just two games in 2017, and while he was a valuable part of the bullpen, he wasn't sure where his career was headed.
Three things happened:
• Stripling began throwing his curveball harder, transforming it from a so-so weapon to an excellent one.
• He came up with a cutter that is also excellent.
• He got an opportunity when the Dodgers' rotation was hit by injuries.
Since entering the rotation in late April, Stripling has been on the short list of the National League's best starting pitchers.
Stripling has won his past five starts with a dazzling 1.15 ERA. In a season when the Dodgers have been ridiculously banged up, he has helped his team to win 17 of 23 games to close its gap from 8 1/2 games to three back in the NL West.
These are the surprise performances that help teams have special seasons. The Dodgers learned that firsthand in 2017, when Chris Taylor remade his swing and became one of the most productive hitters in the game.
Likewise in 2017, the Astros got big -- and somewhat unexpected -- contributions from utility man Marwin Gonzalez and pitcher Brad Peacock after both tweaked their mechanics.
Almost every contender has a similar story. Let's consider 10 others who have impacted this season's division races.

1. Player Page for Max Muncy, 3B/1B/OF, Dodgers
1.011 OPS, 12 HR in 125 at-bats
They make movies out of seasons like this one. Muncy was waived by the Athletics a year ago and spent the 2017 season in the Minors. This season, the 27-year-old utility man has played third, first and the outfield, depending on where he was needed. He has been productive at all of them.
2. Marco Gonzales, LHP, Mariners
7-3, 3.28 ERA, 1.243 WHIP, 7.5 K/9, 13 starts
Mariners general manager Jerry Dipoto traded one of his top prospects, outfielder Tyler O'Neill, to the Cardinals to get Gonzales as the 2017 non-waiver Trade Deadline. He had a 5.53 ERA in parts of three seasons in St. Louis -- but the question was health, not talent. Gonzales has shown this season that when he's healthy, he's capable of being a first-rate Major League starter. He's part of what has made this a magical season for Seattle.

3. Derek Holland, Giants LHP
4-6, 4.54 ERA, 1.292 WHIP, 7.6 K/9, 13 starts
Holland is only 31 years old, with 10 seasons in the Majors under his belt. Where the Rangers once thought he'd reside at the top of their rotation for a decade, he is simply trying to prove he still belongs in the big leagues. Holland has allowed three earned runs or fewer in nine of 13 starts, and while he's not getting deep into games, he has been important for the Giants to survive a string of pitching injuries. He has a 3.83 ERA in his past eight starts.
4. Miles Mikolas, RHP, Cardinals
7-1, 2.27 ERA, 0.958 WHIP, 6.6 K/9, 12 starts
Scouts flocked to Japan to watch Shohei Ohtani and came away with glowing reports about this 29-year-old who got into 37 games for the Padres and Rangers in 2012-14. Mikolas used three seasons with the Yomiuri Giants to refine his delivery, mechanics and preparation. The Cardinals' two-year $15.5 million commitment looks like one of the smartest signings of the offseason.

5. Jesus Aguilar, 1B, Brewers
.890 OPS, 11 HR in 172 at-bats
Before we get to Aguilar, we offer this: Brewers GM David Stearns is really good at what he does. Aguilar got 64 plate appearances in three seasons with the Indians, who could not get him into their lineup. Stearns and his staff saw something they liked. Aguilar was valuable last season --16 home runs in 79 at-bats -- and has been even better in 2018 as a replaced for injured Eric Thames. Aguilar's booming clubhouse presence is also a big factor in Milwaukee's success. Manager Craig Counsell will have to figure out how to juggle playing time now that Thames is back, but that's the kind of problem every manager would like to have.
6. Bud Norris, RHP, Cardinals
13 saves, 3.38 ERA, 1.02 WHIP, 12.6 K/9
The Cardinals are Norris' seventh team -- and sixth in the past four seasons -- and he has reinvented himself as a late-inning reliever. When Greg Holland struggled as St. Louis' new closer, Norris stepped in and reeled off a string of solid performances that won him the job.

7. Max Stassi, C, Astros
.827 OPS, 6 HR in 112 at-bats
Stassi's career was at a crossroads a year ago, when the Astros waived him during Spring Training. No team claimed him, and he did get 31 plate appearances during the season, but he was left off the postseason roster for all three rounds. And then after the season, Stassi did a deep dive into the analytics of his swing and remade his entire offensive game. He is now a valuable platoon partner with veteran Brian McCann, and he is hitting .375 against left-handed pitching. Stassi's 466-foot home run against the Rangers last weekend was the ninth-longest tracked by Statcast™ this season.
8. Wade LeBlanc, LHP, Mariners
2-0, 3.00 ERA, 1.22 WHIP, 7.2 K/9, 8 starts
You kids out there want to learn how to pitch? Check out a video of 33-year-old LeBlanc. It only took 10 seasons in this country and one in Japan to figure out what works for him. LeBlanc basically throws -- wait for it -- fastballs. His best one stays at around 87 mph. LeBlanc will throw some others 77. He'll cut some, too, that land somewhere in the middle. And that's it. His game is not throwing any two pitches the same speed or to the same location and to keep hitters off-balance and guessing.

9. Clay Buchholz, RHP, D-backs
1-1, 1.88 ERA, 0.833 WHIP, 7.9 K/9, 4 starts
Buchholz was a two-time All-Star during 10 seasons with the Red Sox. He finished sixth in American League Cy Young Award balloting in 2010 after winning 17 games and pitching 173 2/3 innings. Injuries and a lack of consistency kept him from getting over the hump. Now with a fresh start with the D-backs, Buchholz has been a huge addition for a rotation decimated by injuries.
10. Matt Adams, 1B/LF, Nationals
.924 OPS, 13 HR in 147 at-bats
Nationals GM Mike Rizzo stocked his system with so many veterans who've rescued the team in a season that could have come undone by injuries. Depending on how manager Dave Martinez balances the playing time once Ryan Zimmerman returns, Adams, who has hit 20 homers only once, could be headed for his first 30-homer season.