How have the Detroit Tigers fared through 40 games?

Roughly one-quarter of the 2015 baseball season has been played, and the Detroit Tigers find themselves in contention for their fifth consecutive American League Central title. There are still 122 games to be played, so a lot has yet to be determined, but 40 games is enough to give us an indication of what kind of team the Tigers are this season.

The 2014 Tigers had a potent offense, finishing the season ranked second in the AL in runs scored. They led the league in team batting average, on-base percentage, slugging percentage, and OPS. The team also led the league in weighted on-base average (wOBA).

The Tigers actually have a better batting average, on-base percentage, and slugging percentage than they had in 2014, so they are hitting the ball as well as any team in the league. This year the Tigers lead the league in hits and rank second in walks and stolen bases. Yet, run production is down from last season's numbers. Strikeout ratio has increased, and Detroit leads the league in grounding into double plays, with 41 rally killers so far this season. They rank second in GIDP percentage in potential double play situations.

Through games of May 18-19, 2015

The Tigers have maintained solid run production mostly without the aid of Victor Martinez, the league's MVP runner-up a season ago. They will have to continue without Martinez, who is currently on the disabled list for an undetermined amount of time with a knee injury. An effective center field platoon and production from the shortstop position have helped to offset the loss of Martinez thus far.

The Tigers rank second to the Houston Astros in stolen bases, and are fourth in the league with a 76 percent stolen base success rate. They are in the middle of the pack in taking the extra base, such as scoring from second base on a single or from first on a double. Fangraphs gives the Tigers a negative base running grade overall, as the slower runners in the lineup have dragged them down, and double plays factor into that. That is one department where Martinez will not be missed.

The 2014 Tigers' starting rotation was not nearly as dominant as they were in 2013, but that was a historically great starting staff. Still, the 2014 Detroit starters led the league in WAR, in part due to leading the league in innings pitched. The Tigers' rotation was second in the league in FIP but 10th in ERA, due mainly to a defense that cost them about half a run per game.

The Tigers' 2015 rotation has allowed a few more runs than the 2014 starting pitchers, but their FIP suggests that improved defense has held their ERA in check. Home runs and walks are up slightly, but strikeouts are down significantly. The departure of Max Scherzer has something to do with that. The Tigers are allowing the same number of hits and base runners, and they continue to lead the league in innings pitched.

Through games of May 18-19, 2015

WAR suggests that this year's rotation is a bit less valuable than last year's crew. They Tigers are currently on pace for 14.4 WAR in 2015, a few wins shy of last season's total. As a group, they have done well keeping the ball in the park, but Anibal Sanchez, who was as good any pitcher in the game in that regard, has fallen apart. Continued steady performances from Shane Greene and Alfredo Simon, along with improvement from Sanchez could add up to a very good starting rotation, which currently ranks fifth in the AL in WAR this season.

Detroit's bullpen was widely viewed as the weakest part of the roster in 2014, and those expectations carried forward into the 2015 season. The 2014 relief corps posted a total WAR that was 0.4 runs below replacement level, dead last in the league. Only Joba Chamberlain was worth 0.5 WAR or better, and he struggled mightily in the second half of the season. The 2014 bullpen continued a recent trend of posting poor overall numbers, but managing to hold the lead better than most teams in the late innings.

The numbers indicate that the 2015 bullpen has improved significantly compared to last season. While strikeouts have declined, their walk rate has decreased by 28 percent. Combine that with a 33-point drop in batting average allowed, and the Tigers relievers have shown an impressive 0.29 decline in walks plus hits per inning (WHIP). That's a 20 percent drop in the number of base runners allowed. Detroit's leading strikeout artist, Al Alburquerque, has seen his strikeout ratio cut in half, while his walk rate has skyrocketed.

Through games of May 18- 19, 2015

When given a lead to protect, the Tigers' bullpen has lost it only twice this season, and only once has that resulted in a Detroit loss. Joakim Soria has been near perfect as the closer, and several other relievers have stepped up their game and are outperforming expectations.

Detroit's bullpen ERA has dropped dramatically, but both FIP and SIERA suggest that there is some good fortune in that number. For one, a three-run homer in the lone blown game by the Tigers' bullpen counts as three unearned runs, on five hits and an error. The Tigers seem to be taking the loss of Joe Nathan in stride, and should Bruce Rondon return and be effective, the Tigers might actually have a decent bullpen heading into the second half of the season.

Fangraphs rates the Tigers' defense 11.6 runs above average through 40 games. That is a distant second in the league to the Kansas City Royals, who are more than doubling up every other team in the majors. By other metrics, Detroit ranks third with +13.8 UZR, and fourth with 12 defensive runs saved (DRS). Detroit's defense is much better after having one of the three worst in the league in 2014.

The Tigers' .575 winning percentage projects to 93 wins, which is more than 2014 when the team won 89 games, but that would currently be only good enough for a wild card playoff spot.

Overall, the Tigers have posted 8.6 WAR for the first 40 games of the season. That projects ahead of their 2014 pace, when the team ranked sixth in the league in fWAR. They currently rank second to the Royals. The two teams are tied atop the league rankings in weighted runs created (wRC+) at 114. The Tigers hold the edge in hitting, but the Royals continue to have better baserunning. Detroit has the better pitching rotation, but Kansas City has the better bullpen and defense. That adds up to a good pennant race.