With a pitching staff decimated by injuries, the Reds have had to use 10 different starters this season, some of whom were completely unknown to most fans before the season started.

Only three pitchers have started more than 10 games, Brandon Finnegan being the only one who was actually projected to be in the rotation before the season began. The other two are Alfredo Simon and Dan Straily.

Simon, coming off a terrible season with the Detroit Tigers, has been even worse this season, and would have been long gone by now without the injuries.

It’s been a different story for Straily. Tossed aside by the Houston Astros and San Diego Padres in spring training, the Reds swooped in and claimed him on waivers. The right-hander has ended up being the team’s most reliable starter to this point.

Straily currently leads Reds starters in ERA (3.34) and fWAR (0.6), having only given up more than three runs one time, which can be forgiven since it came in Coors Field. Aside from Raisel Iglesias (23.6 percent), he is the only member of the rotation to strike out more than 20 percent of the hitters he’s faced (21.1 percent). He has also been the most consistent starter when it comes to throwing deep into games and sparing the bullpen, averaging just under six innings per start — with seven of his last eight outings going six innings or more.

All in all, the organization couldn’t have asked for much more from a last-minute waiver wire addition. Along with Finnegan, Straily has brought some much-needed stability to the rotation.

But could he be due for some regression? There are certainly some signs pointing in that direction.

Despite Straily’s tidy ERA, estimators indicate he hasn’t truly pitched to that level, with each being at least a full run higher than his actual ERA (4.43 FIP, 4.61 xFIP, 4.47 SIERA).

(As always, if you’re unfamiliar with these stats or need a refresher, feel free to give this piece by Steve Mancuso a read.)

Why don’t Straily’s numbers match up?

When it comes to xFIP, it has a bit to do with having home-run-to-fly-ball ratio (11.3 percent) below league average (12.5 percent), so there’s a slight adjustment upward for that. Largely, however, these inflated numbers boil down to having control that escapes him at times. Among 107 qualified starters, Straily has the 12th-worst walk rate (10.5 percent) and is one of just 16 pitchers to have a BB% north of 10 percent. He is also tied for sixth in baseball with five hit batters. When a pitcher walks that many hitters and has a good-but-not-great strikeout rate, ERA estimators typically aren’t too kind.

There are other signs that Straily’s results aren’t painting the most accurate picture about how he’s pitched.

Firstly, his .223 BABIP is quite a bit lower than his career average of .257. There could be a couple of explanations for this:

1.) He’s allowing fewer hard-hit balls than usual, resulting in weaker contact and more outs.

OR

2.) There’s a bit of good fortune involved (i.e., a lot of hard-hit batted balls are going right to his fielders).

It appears to be more the latter than the former for Straily. Here’s a look at his line drive and hard-hit rates in 2016, as compared with his career averages:

straily hard contact rates

In spite of the good results Straily has received, these numbers show that his BABIP will more than likely regress to the mean eventually, and will almost certainly bring along a higher ERA with it if his strikeout and walk rates stay in their current vicinity.

There is one more area that correlates with BABIP and gives further evidence as to why regression could be on the way for Straily: strand rate.

If you’ve watched some of Straily’s starts this year, you’ll notice he’s been particularly good at getting out of jams. Currently, he’s leaving 80.2 percent of runners on base without allowing them to score, good for 18th in MLB. That’s obviously a good thing, but a percentage that high typically cannot be maintained, especially for a pitcher without an extraordinary strikeout rate. There are exceptions to this, like Zack Greinke last season, who had a 86.5 LOB% and a 23.7 K%. However, in most case, strand rate tends to even out over time and trend more toward the league average, which has ranged from 70 to 74 percent over the last 50 years.

These underlying numbers don’t indicate that Straily has pitched poorly by any means and shouldn’t take take away from his performance this year (after all, an ERA in the range of 4.50 would be better a better mark than five of the other nine Reds starters have put up this year). He has undoubtedly been a welcomed addition and pleasant surprise for the Reds. However, there are several reasons to expect some decline from him as the season rolls on.