ST. LOUIS — When Jake Arrieta takes the mound Tuesday against the St. Louis Cardinals, the countdown will begin on what might be his final season with the Cubs and what might be the team’s best chance to win another World Series this decade.
But whatever happens between now and his pending free agency, Arrieta’s legacy in Chicago is assured, his mark on the franchise as indelible in three-plus seasons as any pitcher since Rick Sutcliffe in the 1980s and maybe since Orval Overall more than a century ago.
‘‘I feel that way,’’ Arrieta said of the sizable impact he has made. ‘‘And I tell my close friends and family and teammates that I don’t feel that I have anything to prove. From where I was and where I am now, I think I did plenty of that, proving the naysayers wrong.’’
A pitcher with a losing record and 5.46 career ERA with the Baltimore Orioles, the right-hander — who always had impressive stuff — pulled off the kind of career rebirth with the Cubs that makes the four-player trade in 2013 one of the most lopsided in recent history.
‘‘I don’t even think we’re competitive in ’15 without him,’’ Cubs president Theo Epstein said. ‘‘And we’re not a playoff team without him. Maybe the whole timetable for the rebuild is different without him.’’
Cubs officials from ownership down often talk about left-hander Jon Lester’s $155 million signing before the 2015 season as the turning point in the credibility of the rebuild. The sudden availability and hiring of manager Joe Maddon the same offseason often gets similar billing.
But none of the success the Cubs had that season, which set the stage for a history-making 2016, would have happened without a Cy Young season by Arrieta that featured the greatest 20-game finish for a pitcher in major-league history.
Included in that was a no-hitter against the Los Angeles Dodgers in August and a dominant wild-card victory against the Pittsburgh Pirates. All season, he compensated for a serious lack of pitching depth on the staff.
By last fall, Arrieta had followed an All-Star season in 2016 with a postseason that featured two commanding road victories in the World Series.
‘‘He was the first,’’ said Cardinals first baseman Matt Carpenter, who was college teammates with Arrieta at TCU. ‘‘He was the guy they brought over and thought, ‘OK, we can build around this.’ ’’
Until then, the Cardinals were the dominant team in the National League for more than a decade. Arrieta and the Cubs bounced them from the playoffs in 2015, then beat them for the NL Central title last season.
‘‘Pitching is what dictates the game of baseball,’’ Carpenter said. ‘‘If you’ve got a guy who has a chance to go out there and throw a no-hitter every time he pitches, you’re going to have a chance to win.’’
Not even Epstein saw Arrieta’s dominance coming when he made the trade of his career, sending right-hander Scott Feldman and backup catcher Steve Clevenger to the Orioles for Arrieta and reliever Pedro Strop on July 2, 2013.
Arrieta went 10-5 with a 2.53 ERA for a last-place Cubs team in 2014 after opening the season on the disabled list with shoulder tightness. He followed that with a breakout 2015 in which he went 22-6 with a 1.77 ERA, including 16-2 with a 0.86 ERA in his final 20 starts.
‘‘It was obviously a very special season individually,’’ Arrieta said, ‘‘but it was projected upon the team in such a remarkable way. That’s what I’m most proud of about that season: It allowed us as a team to do so many things.
‘‘It was something bigger than myself. And even though a lot of those things were on an individual level, it was so big for the organization for so many different reasons.’’
He said in spring training that he thought his command was ahead of where it was at this point last year. If that translates to another big season, then the biggest question to be answered next winter might be how many zeros are on some of contract offers he receives.
‘‘We’ll see what happens,’’ Epstein said before the season opener Sunday. ‘‘If we do go through the season and he becomes a free agent, it doesn’t mean he’s not coming back.’’
What few talks the Cubs and Arrieta’s agent, Scott Boras, have had the last two years resulted in little progress, and few seem to think he’ll return to the team after this season.
What’s certain is that Arrieta’s effect on the franchise won’t soon be forgotten, whether he spends six more months or six more seasons in Chicago.
‘‘I’ve always had a chip on my shoulder, and I don’t think the chip is gone,’’ Arrieta said. ‘‘But having to prove that I’m an elite starting pitcher or that I belong here, that’s in the past now.
‘‘Now it’s about, regardless of my individual numbers or stats, I want to win for my team. That’s the ultimate goal. Working toward repeating is all of our main goal.
‘‘The mindset shifts slightly as you get a bit older and as you have some success and progress in this game. But I don’t think the chip will ever completely be off my shoulder. That’s the way I’ve been since I was a kid.’’
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Five of the most impactful pitching acquisitions in Cubs history:
The deal: July 2, 2013, traded from Baltimore, with Pedro Strop and cash, for Scott Feldman and Steve Clevenger.
The impact: The 20-25 right-hander with a career 5.46 ERA blossoms in Chicago, producing a 22-win, 1.77-ERA Cy Young season in 2015 to lead a franchise turnaround that results the following year in their first World Series title in 108 year.
The deal: June 2, 1906, Traded from Cincinnati, with $2,000, for Bob Wicker.
The impact: Cubs led Giants by 1 game in NL; Overall goes 12-3, 1.88 for Cubs, who go on to win league by 20 games before losing to White Sox in World Series; He wins 38 games with sub-2.00 ERAs in 1907, 1908 as Cubs win back-to-back World Series (Going 3-0, 1.11 in those three World Series).
The deal: June 13, 1984, traded from Cleveland in seven-player deal.
The impact: Big right-hander goes 16-1, 2.69 in 20 starts for Cubs, wins NL Cy Young as Cubs extend division lead over Mets from 1½ games to 6½ and advance to playoffs for the first time in 39 years.
The deal: Jan. 4, 1918, traded from Boston Braves for Larry Doyle, Art Wilson and $15,000.
The impact: Career .500 pitcher has best season of career (19-8, 2.00) as Cubs snap three-year streak of losing seasons to reach World Series for first time in eight years.
The deal: July 27, 1945, purchased from Yankees for $97,000.
The impact: Borowy was 10-5 with a 3.13 ERA with the Yankees and finishes 11-2, with league-leading 2.13 ERA rest of way for Cubs, who hold off Cardinals to reach World Series for first time in seven years.