JUPITER, Fla. -- A year ago, Paul DeJong spent Spring Training relearning shortstop after rising through the Cardinals' system as predominantly a third baseman. Now, his status as the club's mainstay at short is cemented for the foreseeable future.

The Cardinals and DeJong agreed to a multi-year contract extension Monday that could keep the shortstop under team control through 2025. The deal, announced at a press conference at Roger Dean Chevrolet Stadium, guarantees DeJong $26 million over six seasons, and includes club options for 2024 and 2025. The options could bring the total value of the deal to $51.5 million, according to sources.

The 24-year-old DeJong didn't make his Major League debut until last May 28, meaning the deal covers his three remaining pre-arbitration years and three additional arbitration years before he can become a free agent in 2024.

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It is the largest contract ever given to a player with less than a year of service time, narrowly edging the six-year, $25 million guaranteed extension reached between the White Sox and shortstop Tim Anderson last spring.

"There are not a ton of zero-to-one service year comparisons out there, but there are some," general manager Michael Girsch said. "We obviously used them."

The 24-year-old DeJong homered on the first swing of his first Major League at-bat last May, then spent the summer slugging his way into the Cardinals' record books. DeJong hit 25 home runs, the most ever for a St. Louis rookie shortstop, while ranking among the National League's top rookies in doubles (26), slugging percentage (.532), total bases (222), RBIs (65) and runs (55).

In all, DeJong hit .285/.325/.532 over 108 games. He finished second in NL Rookie of the Year voting to Cody Bellinger of the Dodgers.

A fourth-round Draft pick in 2015 out of Illinois State University, DeJong ascended rapidly through the Cardinals' farm system on the heels of his prodigious power. He hit 22 home runs at Double-A Springfield in '16, his first full professional season, then 38 between Triple-A Memphis and the Majors in '17. He finished the year as the Cards' primary No.3 hitter and with an .857 OPS that ranked third among MLB shortstops.

"When [principal owner] Bill [DeWitt], [Michael] Girsch and I were discussing the possibility of doing something like this, one thing that stood out about Paul was his intelligence and his ability to adapt and adjust," president of baseball operations John Mozeliak said. "When you think of it from an organizational standpoint, we want to reward the players who have come up through our system, who have showed those types of traits we think are important to invest in. He brought all that to the table."

The deal provides both cost and roster certainty for the Cardinals at a position defined by turnover this decade. DeJong is slated to be the club's 10th different Opening Day starter at shortstop since 2008.

"During my time with the Cardinals, we've always been searching for that shortstop," Mozeliak said. "This does give us a level of comfort, that we've found a player who can play there for a long time."

It's also consistent with the club's preference to extend pre-arbitration-eligible players it sees a future with, a strategy the Cardinals have employed to considerable, if not complete success under Mozeliak.

Similar extensions allowed Adam Wainwright , Carlos Martinez and Matt Carpenter to develop into All-Stars while playing under team-friendly contracts, something the club now hopes happens with DeJong and second baseman Kolten Wong .

The Cardinals did not see the same type of return from a five-year extension they struck with Allen Craig in 2013, or from the multi-year pact outfielder Stephen Piscotty signed last April. Chronic lower body injuries detrailed Craig's career shortly after the extension, and Piscotty was traded to Oakland this winter following a disappointing season.

"I know how hard this game is and I'm relatively new in the big leagues," said DeJong. "For me it's more about a sense of security and going out there knowing the Cardinals are committed to me and I'm committed to them."