Are the Cardinals starters regressing to the mean or are there bigger issues lurking?

Let's face it, the Cardinals starting pitchers are struggling, to say the least.  Over the last week, they have gone 1-3 with a 5.18 ERA and they are 3-7 with a 4.08 ERA over the last two weeks.

Take away Adam Wainwright's starts and the numbers are even worse:  0-3 with a 6.75 ERA over the last week and 2-6 with a 4.73 ERA over the last two weeks (TGFW).

The Cardinals have already replaced Tyler Lyons in the rotation after he gave up 4 runs in 1.2 innings in his last start, but the struggles of regulars Lance Lynn, Shelby Miller and Jake Westbrook have everyone concerned.

Are they just regressing to the mean or are their struggles a sign of bigger issues?  Let's take a look at each of them.

Lance Lynn

Including last night's start, in which he gave up 5 runs in 6 innings, Lynn has an ERA of 3.75, which is in line with last year's 3.78 ERA.  His batting average on balls in play (BABIP) is .290 compared to .321 last year.  With league average usually around .300, one can say that Lynn is not the benefactor of good luck and that he's probably about where he should be.

However, like last year, Lynn is going through a "June swoon".  Since the beginning of June, he has posted an ERA of 5.26.  He has been fortunate to go 3-2 in those 6 starts, thanks in large part to the Cardinals offense.

Last year, Lynn went 2-3 with a 6.66 ERA in June and lost his starting gig as a result.  The Cardinals thought it was a result of fatigue, due to his weight at that time.  However, even after losing weight during the offseason, he appears to be going through the same thing this year.

Looking at Pitch F/X, via Fangraphs, Lynn's average fastball velocity is down slightly from last year, but not enough to cause one to believe he is hiding an injury.

Maybe he is just going through a "dead arm" period and the All-Star break will give him a chance to refresh and reload, but there is no indication of injury or bad luck.

Shelby Miller

Unlike Lynn, Miller doesn't have much major league history to go off of as he only pitched 13.2 innings last year, mostly in relief.  His .290 BABIP is not far off from league average and his 2.82 FIP is not far off from his current 2.79 ERA.

However, like Lynn, Miller has struggled recently.  Over his last 5 starts, he is 2-3 with a 5.55 ERA.

The issue for Miller appears to be mechanical in nature, as he indicated after his last start that he may have discovered a flaw in his delivery. 

He'll test out his theory tonight against the Angels.

Jake Westbrook

Westbrook's BABIP is .299 for the season, which is consistent with league average and his own career mark of .301.  However, his 4.03 FIP compared to his 2.95 actual ERA indicate that he has been the beneficiary of some luck.

Let's face it, pitchers with a career ERA over 4.00 don't suddenly find their ace stuff at age 35 and lead the league in ERA.

So, part of his recent struggles could be seen as a regression to the mean.

However, there are reports that Westbrook's velocity is down and, considering he just came off the DL following a tender elbow, it raises concerns that he is still not 100%.

The have been no reports of any lingering arm issues and maybe he just needs to rebuild his strength after the long layoff, but he is the pitcher I'm most concerned about.

Overall, I'm not too concerned about Lynn or Miller as they are young, do not show any signs of injury and should be able to bounce back.  On the other hand, Westbrook's struggles are concerning and may be an indication that he is not fully healed.  If he doesn't improve soon, he may be headed back to the DL.