Who will eat the innings for the 2018 Cardinals?

Mike Leake was a boring pitcher for the St. Louis Cardinals, just as he was a boring pitcher for the Cincinnati Reds and (briefly) for the San Francisco Giants, and just as he will probably be for the Seattle Mariners.

Throughout his career, Leake has had the kind of performance you could set your watch to. 2017 will likely be the seventh consecutive season in which Leake comes within 0.6 FanGraphs Wins Above Replacement of 2.0, an accepted standard as league average. He doesn't get many strikeouts but he doesn't walk many guys, and from a pure excitement level, he never moved the needle too much for an organization filled with exciting young pitchers.

But one thing that Mike Leake provided for the Cardinals, before his departure to the Pacific Northwest yesterday, were innings. While Leake never pitched a complete game for the Cardinals, and he only has four in his career dating back to 2010, he made at least 30 starts with at least 176 2/3 innings pitched in each season since 2012. If he stays healthy, he should surpass these totals in 2017 as well.

Despite the completely unexceptional nature of Mike Leake, this meant that he had value. Since becoming a full-time starter in 2013, Mike Leake is tied with Drew Pomeranz for 56th best pitcher in baseball per Baseball Reference WAR and is 45th by FanGraphs WAR; while neither is jaw-dropping, he was able to amass this production thanks in large part to his 929 ¹⁄₃ innings, which ranks 16th in that time frame.

While most of the focus of pitcher statistical analysis is rate-based statistics such as earned-run average or fielding-independent pitching, a pitcher who is able to log a significant number of innings at a reasonable level of effectiveness has more value than a pitcher who is less durable or is not able to go as deep into games—durability assured that Mike Leake’s team is less dependent on unreliable minor-league call-ups, and going deep into games allowed the Cardinals to save its bullpen, full of people but not necessarily full of pitchers trusted by Mike Matheny in high-leverage situations, for when pitchers who aren’t as capable of going deep into games are starting.

Entering 2017, the Cardinals seemed to have a decent list of innings-eaters for the rotation. While opening day starter Carlos Martinez had been shut down in 2015 with a shoulder strain, he rebounded in 2016 to throw 195 ¹⁄₃ innings. Adam Wainwright, aside from his Tommy John season of 2011 and his 2015 season in which he was hampered with an (unrelated to pitching) Achilles injury, had thrown at least 198 ²⁄₃ innings in each season since 2009. Lance Lynn, although coming off Tommy John surgery himself, had become a consistent 175-200 inning type of pitcher. And while Michael Wacha was a bit of a question mark, the track records of the top three as well as Mike Leake at #4 made the rotation look relatively safe.

However, the outlook for 2018, as it currently stands, looks quite a bit more variable. Martinez should be fine, at least to the degree that any pitcher should be fine, but Wainwright, who turned 36 yesterday, is presently on the Disabled List and had looked very ineffective since his previous DL stint, topping out on his fastball in the low-to-mid eighties. Lynn is set to become a free agent after 2017 and he has said that there has been “zero communication” between him and the front office about an extension. Wacha has started 24 games this season and has only gone over six innings twice (and one of these starts was 6 2/3 innings).

The Cardinals do have more than their fair share of young, intriguing arms available for 2018, but each comes with his own series of question marks. An obvious internal option to replace Lance Lynn, and now to replace Mike Leake, is the man currently replacing Adam Wainwright—Luke Weaver. Weaver has been spectacular in his two starts of his current stint in the rotation, allowing just two runs in 12 ²⁄₃ innings and striking out ten batters to just one walk in each start. He has shown promise, but his career high for innings in a season was just 119 ¹⁄₃ innings, in 2016. He will likely surpass that total in 2017—he is currently just 12 ¹⁄₃ innings shy of that mark—but expecting him to throw anywhere in the neighborhood of 200 innings is optimistic.

Twenty-one year-old prospect Jack Flaherty will make his debut on Friday, and while a pitcher so young making his debut is certainly cause for excitement, is it fair to expect a 22 year-old to be a stabilizing force in the rotation? In the 2010s, the modern era of keeping a watchful eye on young pitchers, only seven pitchers at age 22 or younger have cleared the 176 ²⁄₃ innings which have become Mike Leake’s standard. And while Flaherty has been working up his innings total in professional baseball, going from 95 in 2015 to 134 in 2016 to 148 ²⁄₃ (and counting) in 2017, expecting a further increase at the Major League level may be too much to ask.

While top prospect Alex Reyes is probably the most anticipated young Cardinals pitcher, his career peak in innings was 111 1/3, a concerning total even before Tommy John surgery sidelined him for 2017. While Reyes was extremely effective in 46 innings at the MLB level in 2016, with a 1.57 ERA and 2.67 FIP, the Cardinals will most likely want to ease him back into a Major League role, perhaps taking some of the high-leverage relief innings which were expected until earlier this month to be handled primarily by Trevor Rosenthal.

At this point, with no further moves, trading Mike Leake seems a bit confounding for a team that hopes to contend for a playoff spot in 2018. For the remaining three years and $38 million (the amount the Mariners will owe him as offset by cash contributions from the Cardinals) on Leake’s contract, he could be classified as a bit of a bargain—despite the relative mediocrity of Leake, FanGraphs pegs his value with the Cardinals at $35.2 million, nearly the value he’d need to be worth the cost for Seattle with seven months of baseball to spare.

If trading Leake is a preamble to the Cardinals extending Lance Lynn or signing a different starting pitcher in the off-season, the logic tracks a bit more—the Cardinals would begin 2018 with two dependable starters (Martinez, Insert Name Here), a formerly dependable starter who could have a renaissance but is not a guarantee for one (Wainwright), Michael Wacha (whatever he counts as), and a young starter (probably Weaver, at least initially).

But even if this is the case, Lynn will probably command considerably more than the $12.7 million that the Mariners will be paying Leake. While Lynn certainly has the higher upside—after all, he has been an All-Star and is currently in his Tommy John recovery year—he also may have the lower floor, as his peripherals in 2017 have been far below his run suppression, suggesting that he is a regression candidate.

And if the Cardinals avoid Lynn and do not sign another (at least) mid-tier free agent starting pitcher, their ceiling may not decline too much—the team is loaded with promising young pitchers. However, as none of these pitchers have exhibited the MLB reliability of Mike Leake, the floor should drink dramatically, and it is entirely possible that the Cardinals will come to regret this trade as a concession to what could be rather than the boring adequacy that a pitcher like Leake provides.