On Tuesday, the St. Louis Cardinals announced that they had signed Miles Mikolas, 2018’s surprise starting rotation revelation, to a four-year contract extension which will keep him in St. Louis through 2023. His contract will remain the same for 2019, but starting in 2020, Mikolas is slated to make $17 million per season.

It had been rumored throughout the off-season that the Cardinals were looking to extend Mikolas, whom the team signed to a two-year, $15.5 million contract before the 2018 season following his successful stint in Japan’s Nippon Professional Baseball, which itself followed a far less successful stint in Major League Baseball with the San Diego Padres and Texas Rangers.

The initial signing came with some level of risk–no, a pitcher that you expect to crack your starting rotation is not going to hamstring your organization by making $7.75 million per year, but had Mikolas’s return to MLB played out similarly to his sub-Replacement Level first act, it would have been a tough pill for the Cardinals to swallow. But as it turned out, the signing turned out to be one of Major League Baseball’s greatest moves during the off-season, as Mikolas went from the team’s de facto fifth starter to start 2018 to the man scheduled to start 2019’s season opener, thanks to a 2018 campaign in which he cruised to a 18-4 record, with a 2.83 ERA in over 200 innings.

Advanced pitching metrics make Mikolas’s 2018 look a little bit less glamorous than his surface level stats–opposing batters’ mediocre .279 batting average on balls in play and a 76.2% left on base rate suggest that Mikolas got a bit lucky, and an 18-4 record is only made possible with sufficient run support–but by any measure, he far surpassed the expectations of his contract. FanGraphs Wins Above Replacement, which placed a higher premium on his higher (3.28) FIP and (3.67) xFIPs than his ERA, still saw Mikolas as worth 4.3 fWAR, which translates to a free agent dollar value of $34.5 million.

If Mikolas repeats his 2018 performance in 2020 through 2023, without even the slightest bit of improvement, this contract will be an extreme bargain for the Cardinals. He would break even on the cost of the contract in September 2021 and solidify a rotation that otherwise was looking a bit thin (incumbent starters Michael Wacha and Adam Wainwright are set to become free agents after 2019). And if Mikolas repeats his 2018 performance in 2019, the cost of Miles Mikolas in free agency would only go up, as he suddenly looks like a safe bet who genuinely turned a corner in Japan rather than a one-hit wonder.

But this is a risky contract for the Cardinals. It wouldn’t be fair to compare it to the contract extensions signed recently by the likes of New York Yankees center fielder Aaron Hicks or Minnesota Twins right fielder Max Kepler–those low-cost extensions were buying out years of team control, and the amount paid by the Cardinals was inevitably going to have to come closer to his true free market worth rather than spinning off of artificially-suppressed years of team control. But this was still a contract signed a year before it was required that the team do so.

In a way, this contract screams 21st century St. Louis Cardinals. In an era where velocity is the name of the game, and high strikeout rates take priority over durability, Mikolas is a bit of a throwback–of MLB’s 57 pitchers in 2018 to throw enough innings to quality for league leaderboards for rate statistics, he had the fourth-lowest strikeout rate. Of the three with lower strikeout rates, one was terrible (Lucas Giolito), one was mediocre (Ivan Nova), and the third has also signed a multi-year, $16 million per season contract with the Cardinals (Mike Leake). And yet Mikolas clearly transcended this level of pitching–he struck out 6.55 batters per nine innings in 2018, while the next lowest strikeout rate among those who were more valuable than him was nearly three strikeouts per game higher, the 9.32 K/9 of Cleveland Indians starter Mike Clevinger.

But this was also, for an organization which has built a reputation for better or worse for its conservatism, a bit of a risk. The upside has already been stated–that Mikolas is a legitimate #1 or #2 type starter, and that he is being paid roughly what the Boston Red Sox just paid Nathan Eovaldi, who has been better than average by ERA in two of his seven MLB seasons and is constantly injured. But the downside is also fairly steep–while even Mikolas optimists expect some regression from 2018, there is a big difference between the 3.5 fWAR projected pitcher of ZiPS projections and the pitcher we saw in the early parts of his career.

Mikolas optimism is predicated on his pinpoint control–this is how a pitcher who doesn’t strike out very many batters can survive–but prior to last season, he walked 3.35 batters per nine innings. This isn’t terrible, by any means, but it’s pretty underwhelming for somebody who doesn’t strike guys out. This might be reading too much into 91 1/3 innings stretched out over three seasons, but the only reason this contract was signed in the first place was extrapolating one season’s worth of data as a substantial sign of future performance.

Evaluating this contract from a statistical perspective is particularly difficult because of how little evidence we have about Mikolas. His 2012-2014 numbers are perhaps a bit stale at this point, but it is also reckless to look exclusively at 2018. We can look at his NPB stats and see improvement, but adjusting those numbers for the higher level of competition in Major League Baseball is at best an inexact science. And this isn’t the Paul DeJong extension, where we are basing conclusions based on little MLB data but also the team is buying out six years of team control–this is much closer to a true MLB free agent contract. And while some questioned the signing at the time because of how unproven DeJong was, his value only went up as he more or less repeated his promising 2017 in 2018. Mikolas is being paid with the expectation that he is good, not the expectation that he will be 2018 Miles Mikolas every year. If the latter were the case, he would be nearly doubling his new annual salary.

The most likely scenario, at the risk of sounding like a centrist for the sake of preserving harmony, is that Mikolas has improved from the sub-Replacement Level pitcher he was in his first stint in the Majors (assuming he actually was that bad in the first place, which he probably wasn’t) but that he isn’t a down-ballot Cy Young candidate like he was last season. And the obvious parallel in recent years from the Cardinals was Mike Leake, who was worth $34.9 million in his eleven months with the team before he was traded to the Seattle Mariners. While his performance was unexceptional, there is value in having a league-average-ish pitcher. And there is perhaps more of a sense of urgency in signing Mikolas than there was in signing Leake–the 2015-16 Cardinals had a larger reserve of young, average-ish pitchers waiting in the minors than they do now, where there are serious doubts about what the rotation will look like in 2020, particularly if injuries to Alex Reyes and Carlos Martinez remain a hindrance. And in the event that the Cardinals essentially signed Mike Leake 2.0, that may not be the worst thing.