There's no doubt about it -- Astros right-hander Gerrit Cole is authoring one of the greatest walk years of all time. And with each blistering fastball and mesmerizing hook, the 29-year-old further improves his resume heading into free agency.

The list of hurlers to hit the open market in their primes is replete with All-Stars, Cy Young Award winners and Hall of Famers. But given the combination of Cole's age and performance in an era when the 200-inning workhorse has become a rare breed, there's a strong case to be made that Cole will be the best free-agent starter since Greg Maddux in 1992.

Here's how Cole stacks up against some of the other big-name starters who became free agents in that timeframe.

(Note: Year and seasonal age listed for each player's final season before free agency.)

Gerrit Cole, 2019 (age 28)
Career stats: 127 ERA+, 3.22 ERA, 21.1% K-BB%
Walk-year stats: 212 1/3 IP, 185 ERA+, 2.50 ERA, 326 K

After a breakout year in 2018, Cole got even better in '19, especially down the stretch. The righty set a Major League record by striking out double-digit batters in nine straight starts to close out the regular season, posting a 1.61 ERA in that span and becoming the 18th pitcher in modern baseball history to notch 300 K's in a single season along the way. His first start this postseason was another gem, as he struck out 15 Rays over 7 2/3 scoreless innings. His stock heading into free agency is about as high as it gets.

David Price, 2015 (age 29)
Career stats before free agency: 126 ERA+, 3.09 ERA, 17.1% K-BB%
Walk-year stats: 220 1/3 IP, 164 ERA+, 2.45 ERA, 225 K

Price nearly won his second career American League Cy Young Award in 2015, excelling for the Tigers and then dominating following an in-season trade to the Blue Jays. Although he struggled in the postseason that year, he ended up signing the largest contract ever for a pitcher -- seven years, $217 million with the Red Sox. Still, Cole's numbers and age give him the edge.

Zack Greinke, 2015 (age 31)
Career stats before free agency: 122 ERA+, 3.35 ERA, 16.0% K-BB%
Walk-year stats: 222 2/3 IP, 222 ERA+, 1.66 ERA, 200 K

Greinke had three years and $71 million remaining on his contract with the Dodgers, but he opted out after recording a microscopic ERA in 2015, joining Price on the free-agent market. Just days after Price signed with Boston, Greinke joined the D-backs for $206.5 million over six years. However, Greinke was heading into his age-32 campaign at that point, with more than 2,000 innings on his odometer (Cole is just north of 1,200 now, postseason included).

Max Scherzer, 2014 (age 29)
Career stats before free agency: 117 ERA+, 3.58 ERA, 18.1% K-BB%
Walk-year stats: 220 1/3 IP, 123 ERA+, 3.15 ERA, 252 K

Cole shares some similarities with Scherzer five years ago, as the latter entered free agency after delivering the best two seasons of his career to that point. The team that lands Cole will be hoping it turns out as well as the Scherzer signing (7 years, $210 million) has for the Nationals. But as far as their free-agent candidacies are concerned, Cole is younger than Scherzer was and has the slight advantage performance-wise as well.

CC Sabathia, 2008 (age 27)
Career stats before free agency: 120 ERA+, 3.66 ERA, 12.6% K-BB%
Walk-year stats: 253 IP, 156 ERA+, 2.70 ERA, 251 K

Like Cole and Scherzer, Sabathia did his best work leading up to free agency, winning the AL Cy Young Award in 2007 and carrying the Brewers to the postseason with a 1.65 ERA and seven complete games over 17 starts following an in-season trade in '08. But save for that stretch, Sabathia was never quite as overpowering as Cole has been the past two seasons. The big lefty did have youth on his side, though, and he ultimately signed with the Yankees for $161 million over eight years.

Pedro Martinez, 2004 (age 32)
Career stats before free agency: 168 ERA+, 2.71 ERA, 22.2% K-BB%
Walk-year stats: 217 IP, 124 ERA+, 3.90 ERA, 227 K

From 1997-03, Martinez produced one of the most impressive stretches by a pitcher in baseball history, posting a 213 ERA+ and winning three Cy Young Awards. But by the time he reached free agency in the 2004-05 offseason, the wiry righty was 33 years old and showing some signs of decline. The Mets scooped him up for $53 million over four years.

Mike Mussina, 2000 (age 31)
Career stats before free agency: 130 ERA+, 3.53 ERA, 13.0% K-BB%
Walk-year stats: 237 2/3 IP, 125 ERA+, 3.79 ERA, 210 K

While Mussina was decidedly above average during his tenure with the Orioles, his performance rarely reached the level of a bona fide ace, and he was about to turn 32 years old when he joined the Yankees on a six-year, $88.5 million deal in December 2000.

Randy Johnson, 1998 (age 34)
Career stats before free agency: 129 ERA+, 3.36 ERA, 16.7% K-BB%
Walk-year stats: 244 1/3 IP, 135 ERA+, 3.28 ERA, 329 K

If the Big Unit was a few years younger when he hit the open market in the 1998-99 offseason, his free-agent candidacy might have been stronger than that of anyone else on this list. The left-hander posted a 1.28 ERA over 11 starts following a July trade to the Astros and finished the 1998 campaign with 329 K's, topping the 290-mark for the fourth time in six years. However, he had recently turned 35 years old when he became a free agent. The southpaw ended up signing a four-year, $52.4 million deal with the D-backs, and he defied Father Time by winning four straight Cy Young Awards.

Kevin Brown, 1998 (age 33)
Career stats before free agency: 125 ERA+, 3.30 ERA, 9.4% K-BB%
Walk-year stats: 257 IP, 164 ERA+, 2.38 ERA, 257 K

After a solid but unspectacular start to his career, Brown signed with the Marlins in December 1995 and soon morphed into an ace, recording a 2.33 ERA over the next three years and helping two different clubs reach the World Series. However, '98 -- his age-33 campaign -- was the first time he struck out more than 7.8 batters per nine innings. The veteran became baseball's first $100 million man when he joined the Dodgers that December.

Roger Clemens, 1996 (age 33)
Career stats before free agency: 144 ERA+, 3.06 ERA, 15.2% K-BB%
Walk-year stats: 242 2/3 IP, 139 ERA+, 3.63 ERA, 257 K

Clemens' 1996 season represented a bounceback effort for the veteran, but he still appeared to be entering the twilight of his career when his Red Sox tenure came to an end. Few could have predicted he'd go on to win four more Cy Young Awards, including back-to-back in '97-98.

John Smoltz, 1996 (age 29)
Career stats before free agency: 116 ERA+, 3.45 ERA, 12.1% K-BB%
Walk-year stats: 253 2/3 IP, 149 ERA+, 2.94 ERA, 276 K

There was a lot to like about Smoltz when he became a free agent after the 1996 campaign. He was coming off a Cy Young Award-winning season, was a four-time All-Star and had proven to be a postseason stud, and the Braves were quick to re-sign him. It may be splitting hairs to give the advantage to Cole based on his age and lesser workload, though he also has a statistical edge.

David Cone, 1992 (age 29)
Career stats before free agency: 114 ERA+, 3.10 ERA, 14.6% K-BB%
Walk-year stats: 249 2/3 IP, 129 ERA+, 2.81 ERA, 261 K

Although Cone is best remembered for his time with the Yankees in his 30s, he was terrific for the crosstown Mets early in his career and helped the Blue Jays win the World Series in 1992 before becoming a free agent and signing with the Royals. While Cone's career stats at the time were stellar, he was older than Cole is now and wasn't nearly as dominant in his walk year.

Greg Maddux, 1992 (age 26)
Career stats before free agency: 115 ERA+, 3.35 ERA, 8.0% K-BB%
Walk-year stats: 268 IP, 166 ERA+, 2.18 ERA, 199 K

As evidenced by the aforementioned names, pitchers of Maddux's caliber do hit the free-agent market every so often. It's just that they rarely do so at 26 years old. That's how old Maddux was when he posted an incredible 2.18 ERA for the Cubs in his walk year and then signed with the Braves for $28 million over five years. In the five years before free agency, Maddux recorded a collective 3.01 ERA (126 ERA+) and averaged 251 innings per season.