Is the St. Louis Cardinals' reliever usage pace sustainable?

The St. Louis Cardinals own a 10-4 record (.714 winning percentage) so far this young season despite scoring at a rate of 3.93 runs per game. The reason? The Cardinals have received excellent pitching so far this young season. Opponents have plated just 32 runs against the Cardinals through 14 games. Put otherwise, St. Louis pitchers have held the opposition to 2.29 runs per game. The Cards' +23 run differential gives them a 10-4 Pythagorean record which mirrors their tally in the standings.

The Cardinals starters' run prevention has allowed them to work deeply into games. So far this year the St. Louis rotation is leading all of baseball, averaging 6.38 innings pitched per game. The Tigers rank second with 6.375 (and the Orioles last with 4.83).

This is the St. Louis blueprint. The starters go deep into games, which allows manager Mike Matheny to use relievers based more on desire than need. Matheny has rarely had to go to the bullpen early in games this year, though he has been forced to use relievers in extra innings on a couple of occasions.

Matheny has leaned hard on certain relievers through the first 14 games. Closer Trevor Rosenthal and setup man Jordan Walden have each already received at least one day off this season. With the numerous off-days I found this somewhat surprising, so I thought I'd see how Matheny's use of individual relievers compares to MLB overall this year and last.

The following chart shows the how the individual St. Louis relievers' usage stats compare to other relievers across MLB so far this year in the statistical categories of appearances (App), innings pitched (IP), total batters faced (TBF), and number of pitches (NP). When viewing the ranks keep in mind that 263 relievers have faced a batter in the majors so far this season. Also be aware that the Cardinals have played 14 games this year, which ties them for fewest in the majors. I listed the relievers from highest number of pitches thrown (NP) to lowest.

2015 St. Louis Reliever Usage

It's early in the year. Teams have had more off-days than they typically will in a three-week stretch at any other point in the season due to the built in off-days after openers. Consequently a lot of managers are using relievers at rates that are unsustainable over the long haul of the 162-game season. For a greater perspective on the Cardinals' current reliever usage rates, I decided to compare them to last season's regular-season totals for individual relievers. I calculated the individual St. Louis relievers' per team game rates for each stat and then extrapolated them out over 162 games. Here's how they compare to the MLB reliever usage stat ranks for 2014.

2015 St. Louis Reliever Usage Rates vs. 2014 Reliever Usage Totals

This table is startling. Matheny is on pace to use four Cardinals relievers more than any manager used any reliever in 2014. The Cardinals' current bullpen usage patterns are unsustainable.

It's amazing that Choate is on pace for a top-ten finish in appearances while simultaneously on a trajectory to face just 75 batters. Matheny has deployed the southpaw specialist as a one-out guy in the extreme so far this year. The lefty is on pace to make 75 appearances and face 75 batsmen. This lends credence to Matheny's complaint that Randy Choate's inclusion in the relief corps kills the other pitchers in the pen. The LOOGY collateral damage in the pen is plainly visible so far this season.

It appears that we might also be able to include Carlos Villanueva in the category of specialty relievers whose role places an undue burden on his fellow bullpenners. What good is a long man if the manager only calls on him once per week and then for only 2 2/3 innings total? Not that I blame Matheny. Watching Villanueva pitch is painful, especially in extra innings.

It's extremely early in the year, but so far Matheny has employed a bullpen strategy that sees him call on multiple relievers an inning while playing the matchups. When coupled with the low-scoring environment, a number of close games, and his devotion to fixed bullpen roles, this has caused him to lean heavily on Seth Maness, Kevin Siegrist, Walden, and Rosenthal. Matheny won't be able to rely on that quartet as much as he has so far in April over the course of the 162-game season. Something will need to change with respect to the bullpen: usage or composition.

FanDuel

The Brewers are in bad shape. Carlos Gomez, Scooter Gennett, and Jonathan Lucroy are all on the DL. Carlos Martinez, Adam Wainwright, and Lance Lynn—all members of the rotation with the lowest ERA in the majors so far this year—are slated to start against the Brew Crew in Milwaukee this weekend. Play FanDuel here.