Hoyt Wilhelm had already established himself as an All-Star reliever by 1959. That's when the future Hall of Famer, at age 36, embarked on what would be his only season spent primarily as a starting pitcher -- and he was still outstanding. The knuckleballer led the Majors with a 2.19 ERA over 226 innings for the Orioles.

Pitchers moving from the bullpen to the starting rotation is nothing new. There were instances in the 1980s and '90s of pitchers dealing well with the role change, such as Charlie Hough and David Wells. But the number of pitchers making the switch has increased in the 21st century. Derek Lowe, Johan Santana, Adam Wainwright, Chris Sale and Michael Lorenzen are some of the more notable examples. And this season, as teams try to find creative ways to fill innings, the relievers-turned-starters movement is having a moment.

Here are seven hurlers who are thriving after transforming from reliever to starter either this year or in 2023. There are others worth mentioning, such as the Brewers' DL Hall, the Marlins' A.J. Puk and injured Red Sox righty Garrett Whitlock, but the early-season performances from those in this group stand out.

All stats updated through Thursday.

CONVERTED THIS SEASON

Jordan Hicks, Giants
Just four games in, Hicks' results as a starter this season have already exceeded his 2022 attempt to make the transition with the Cardinals. He made eight starts that year and recorded a 5.47 ERA with 21 walks issued in 26 1/3 innings before a forearm strain ended the experiment. He's already logged 23 innings this year and has a 1.57 ERA with only six walks.

The 27-year-old has made his career by throwing really hard -- sometimes up to 104 mph. That made him a dominant reliever at times in St. Louis, although he often struggled to command that heat. But unlike in 2022, when his go-to sinker still averaged triple digits, Hicks has become a different pitcher. He's pulled back 3-6 mph on all of his pitches, which has led to better command. He's still posting a high ground-ball rate (58.1%) with his 96 mph sinker. Meanwhile, his splitter and sweeper, two relatively new weapons in his arsenal, have baffled the opposition. Hitters are 2-for-25 with 11 strikeouts in at-bats ending on those pitches.

Reynaldo López, Braves
A former Top 100 Prospect, López logged 446 2/3 innings and 81 starts for the White Sox from 2017-20. That four-year run had more valleys than peaks, as evidenced by his 93 ERA+. The right-hander allowed an MLB-high 110 earned runs in 2019 and finished the shortened 2020 season with a 7.63 FIP in 26 1/3 frames. López's career was rejuvenated when he became a full-time reliever in 2022. He produced a 2.76 ERA and a 1.93 FIP across 61 appearances that year, and he was solid again last year while pitching for the White Sox, Angels and Guardians.

But the Braves made their intentions clear when they signed López this winter: He would be stretched out to start once again. Dominating with a mid-90s fastball and a mid-80s slider, Lopez has given up only one run and struck out 18 batters through his first 18 innings. With Spencer Strider out for the season following elbow surgery and the Braves' other starting pitchers combining for a 6.07 ERA, the decision to put López into the rotation has paid off handsomely for Atlanta.

CONVERTED LAST SEASON

Ronel Blanco, Astros
Blanco appeared in 157 professional games from 2018-22 -- ranging from High-A to his debut with the Astros. He was a reliever in all but two of those contests. He then started 13 games at Triple-A and seven more at the big league level last year. Start No. 8 was the stuff dreams are made of. But Blanco is not some one-game wonder. He held the Rangers hitless into the sixth inning of his next start and didn't allow his first run until he was 15 innings deep into the season. He is the first Astros pitcher to open a season with three consecutive quality starts since Gerrit Cole in 2019, when he was the AL Cy Young runner-up. Blanco has the lowest opponents' batting average (.090) among qualified pitchers and has held those hitters to a scant 21.4% hard-hit rate.

Michael King, Padres
Last year wasn't King's first foray as an MLB starter; he garnered a handful of starts with the Yankees in 2020 and 2021. But last year was the first time King got an extended look in the rotation, and he responded with a 2.27 ERA through six September starts spanning 31 2/3 frames. The Padres definitely saw what the 28-year-old accomplished and made him the centerpiece of their return in the Juan Soto trade last December. King's first two turns with San Diego included 10 walks through 7 1/3 innings, but he has been much more in command over his past three starts, including a flirtation with a no-hitter on Wednesday. King's sweeper and changeup, which comprise about 45% of his pitch usage and shined for him last season, have led to only five hits and 17 K's in 47 at-bats.

Cristopher Sánchez, Phillies
Debuting in 2021, Sánchez spent most of his first two Major League seasons as a multi-inning reliever and came away with a 75 ERA+ through those 52 1/3 innings. However, the lefty has a long history of starting in the Minors, and he blossomed once he became a staple of the Phillies' rotation in June of last year, producing a 3.35 ERA over 94 frames (17 starts). He notched 10 strikeouts in his final start of that season, much like he did Wednesday in a win over the Rockies. Thanks to his 1.99 FIP, Sánchez has already accrued 0.8 fWAR this season, tying him with teammate Zack Wheeler for the fourth-most in MLB. He has also made noticeable reductions in his barrel rate (5.1%, down three percentage points from last year), sweet-spot rate (25.4%, down about six points) and hard-hit rate (32.2%, down eight points).

Seth Lugo, Royals
Lugo was a solid starter last season for San Diego, registering a 3.57 ERA over 26 turns with the Padres. This season? He's been more than solid. Per teammate Vinnie Pasquantino, the 34-year-old has been "ridiculous." That's an appropriate description of someone who has given up only three runs in 25 2/3 frames. Lugo was once an extremely effective, high-strikeout reliever for the Mets. After making 18 starts for New York in 2017, the righty recorded a 3.25 ERA and a 10.3 K/9 rate over five seasons spent mostly in the bullpen. Lugo has only 13 K's this year, but he's getting the job done by inducing a lot of weak contact (33.3% hard-hit rate). He has allowed only four barrels through four starts.

Zack Littell, Rays
Littell was never really viewed as a starter at the Major League level until after he joined the Rays as a waiver claim in May of last season, his sixth in MLB. And Tampa Bay's decision to begin converting Littell in July was likely born out of necessity as much as desire because the club had a bunch of starting pitchers on the injured list. But the right-hander has rewarded the team's faith with a 3.07 ERA through 15 starts (85 IP) dating back to July 30. He's got a 2.14 ERA through four starts this year. Littell has been leading with his slider, which is one of the most valuable pitches in the game. His K rate on that pitch has nearly tripled from last season (7.4% to 21.4%). That's a big reason why his overall strikeout rate has made a five-point leap from last season, up to 24.7%.