Tigers' Ian Kinsler is already starting to decline

Throughout the offseason, Detroit Tigers fans have been quick to point out the holes and problem areas on the roster. Left field was a point of contention for weeks, and only after general manager Al Avila acquired three new relievers to remodel the bullpen. Now, fans are concerned about the bottom of the lineup, and whether young players like Nick Castellanos and James McCann will pull their own weight.

But what about the top of the lineup? Specifically, I'm referring to Ian Kinsler, a 33-year-old second baseman who has warded off Father Time at a position that is historically very hard on 30-somethings. Kinsler hit .298/.342/.428 last year, his best offensive season since 2011 according to wRC+. He hit 11 home runs, stole 10 bases, and scored 94 times. According to fWAR, he was the fourth-most valuable second baseman in the game last season.

There are signs for concern, though. Tony Blengino of FanGraphs looked at the batted ball profiles of all second basemen from 2015, and found a few red flags in Kinsler's numbers.

There are clear warning signs, and the life raft of a very low K rate, within Ian Kinsler‘s profile. Kinsler no longer hits the ball hard with any degree of regularity, and his very high 2015 liner rate is way out of whack with career norms. Even with all of those liners, he had a below average (98) contact score. Many of those liners are going away, likely dragging his OPS+ below 100 in 2016 and beyond.

Kinsler posted a 25.4 percent line drive rate in 2015, the highest of his career and well above his career average of 20.6 percent. He reached base on 67.3 percent of those liners, slightly above MLB average. This helped him post a .296 batting average, his highest figure since 2008.

However, Blengino's criticisms appear accurate. Kinsler's batting average on balls in play was .323, also his highest since 2008. His exit velocity on line drives averaged 89.7 miles per hour in 2015, just above the MLB average of 89.2 miles per hour on all balls in play. His average exit velocity on all balls in play was 86.4 miles per hour, which ranked just behind Stephen Drew. Line drive rate is a statistic that does not typically carry over from year to year -- a few players excluded, of course -- and Kinsler will probably regress to career norms in 2016.

The drop in exit velocity might be even more damning. Kinsler has a bit of an uppercut in his swing, leading to a fly ball rate of 44.1 percent for his career. That is the fourth-highest rate among second basemen (min. 1,000 plate appearances) since Kinsler's major league debut in 2006. While his high pop-up rate results in plenty of easy outs throughout the season, he has hit for enough power to more than offset that deficiency.

However, Kinsler only homered on five percent of fly balls in 2015, the lowest rate of his career. Conventional wisdom suggests that he would regress (in a positive direction) to league norms this season, but his below-average exit velocity indicates that his power may be declining. A steady decline in his ISO figures -- he has been at least 25 points below his career average in the past three seasons -- reinforces this hypothesis.

Unfortunately, Kinsler's decline in power and potential batting average regression is magnified by a declining walk rate. After walking in 9.6 percent of plate appearances in eight years with the Texas Rangers, Kinsler has walked in just 5.1 percent of plate appearances with the Tigers. He was slightly better in 2015 than 2014, but a decline in average could result in a 2014-like dip in his on-base percentage.

Luckily, these stats are not a guarantee that Kinsler will regress in 2016. While some drop-off is likely, he still sports a very low strikeout rate, and should be successful given the sheer volume of pitches he puts into play (not to mention the value his glove provides). This could also be a one-year blip, or the product of a change in approach we haven't picked up on yet. However, given his age and the numbers we have at our disposal, it seems more likely that we will see a slightly diluted version of Kinsler in 2016.