Is it the right call to move on?

There is no doubt that Zac MacMath has had growing pains during his development in Philadelphia. Criticism of him has been fair in years prior, but as the goalkeeper improves so does the intensity of his critics. Perhaps patience is lacking from the fan base (given other circumstances it's hard to blame them). On the other hand maybe increased frustration at struggles with another option on the bench is accelerating the calls for Zac's head.

Either way, Nick Sakiewicz signed Algerian number one goalkeeper Rais M'Bolhi this August. The timing was strange, with the team needing help offensively and MacMath playing some really good soccer, but the move delighted those most negative about the play of the young, still developing goalkeeper. M'Bolhi has been back and forth from Algeria playing in African Cup of Nations qualifying  and only playing just a handful of games for the Philadelphia Union, but he certainly hasn't done much to impress and plenty to infuriate. Yes, one play was enough to infuriate.

It's all too strange for me personally. I wonder just why we brought in a goalkeeper halfway through the season when we had two quality starters already in tow. It seems as though Sakiewicz has put his eggs in the Rais M'Bolhi basket, and it would be truly peculiar to keep three starting-quality goalkeepers on the roster when depth is needed so glaringly in other positions. So the question I beg is have the Union given up on Zac MacMath too early?

We always wonder about things here at the Brotherly Game (sometimes when we wonder we often hurt ourselves), and this question is all too intriguing to me. How does Zac MacMath compare to other goalies in MLS? More specifically, how does he compare to great goalkeepers - guys like Tim Howard, Brad Guzan, and Nick Rimando - who have played through their development in MLS? How does he compare to keepers at the same age as him, such as Bill Hamid and Sean Johnson. Personally, I've never seen too much between Hamid, Johnson, and MacMath overall - and I already can hear people exiting out of this article at those words (Please keep reading).

So our main data man, Jared Young, did some beautiful data work and compiled all of the statistics from every goalkeeper to ever play in MLS. We decided to break it down to the most important goalkeeping stat which is Save Percentage Adjusted (explained later) and we've come up with the most telling information from said database:

The chart above shows the save percentage rate adjusted to the league average during the season in which a goalkeeper recorded their save percentage rate. For example, if Zac MacMath recorded a save percentage rate of 69% (as he did in 2013) yet the league average at the time was, say, 65%. Adjusted, the league average would be represented by 1 (the green horizontal line in the chart) and Zac's save adjusted save percentage would be above 1 given his performance. Now, this chart is organized based on age showing that on average goalkeeper steadily improve as they increase in age. The most defining improvement occurs after the age of 30 in a lot of cases in MLS. Reminder, Zac MacMath is only 23.

Now another comparison we needed to make was clear. Sure, everyone knows goalkeepers are like a fine wine - only improving with age. But how did the young American MLS goalkeepers fair before they ripened with experience? The graphic above shows save percentage adjusted of ten MLS goalkeepers prior to the age of 24. At the top of the list is Sean Johnson, which surprises me, and Chris Seitz is hovering at the bottom, which is not surprising to me. This graphic finds Zac squarely in the middle of the pack, just under the likes of Brad Guzan and Seattle Sounders starter Stefan Freiand above the likes of seldom heard of Adin Brown and DJ Countess.

If the goalkeeper's room for improvement typically accelerates around 30, and Zac is performing early in his career slightly under par than some terrific goalkeepers, is it safe to say he will join them? There's two routes he can go, but Zac is on the path to improving especially given how young he is.

Do you think he will join those big names? Take our poll and let us know what you think in the comments section below!