Do the Union have a deep enough bench?

Fingers crossed the Philadelphia Union will sign their striker soon and complete their key offseason acquisition. The rest of this post actually pretends this is the case and that coach Curtin has kept his word. With a new striker and a stable midfield that was mostly acquired in the spending frenzy last offseason, the Union would have a starting XI that has the quality to make a playoff run. Notice I said starting XI.

While the focus of the offseason has been on acquiring top line talent, the Union have notably avoided adding depth anywhere in the midfield or on defense. At the top, the Union added C.J. Sapong and resigned Conor Casey to bolster what should be a strong forward corp. Second round draft pick Dzenan Catic appears ready to be the fourth player in the rotation, rounding out a good mix of young talent with a crafty veteran.

In the midfield and on defense the team has only lost players from last season's roster. Amobi Okugo and Zac MacMath are the notable players lost. In the interim the Union passed during two re-entry drafts and then on players like Michael Farfan who had to go through the Allocation Order to be selected by D.C. United.

The Union's depth is definitely looking shaky, but the question remains, do they have enough?

How much depth does a team need?

To understand if the Union have enough depth the first thing that needs to be understood is how much reserves play. Looking at 2014, the top eleven players (ranked by minutes played) on each team played an average of 75 percent of the minutes. That leaves 25 percent for the reserves. It's worth noting that of the ten teams whose eleven top players played more than 75 percent of the minutes, eight of them earned more than 50 points. Where reserves played more than 25 percent of the minutes only one team in eight scored more than 50 points (that team was FC Dallas). For those of you who need to see it to believe it here is a chart that bares it out.

Chart originally appeared on AmericanSoccerAnalysis.com

That's a pretty clear indication you want your best XI on the field as much as possible. Not rocket science, but good to know how important that mix of starter and non-starter is.

Therefore, the Union should target at most 8,415 minutes for their reserves, 24 percent of all minutes played across 45 games. Shortly, we'll look at how many minutes can be expected from the Union bench, but first let's look at the starters to see what it would take for them to play 75 percent of the minutes.

How much will the starters play?

Here are the 2014 minutes played by the projected starting lineup for this season.

Adding up last season's minutes the Union fall about 2,000 short of the 75 percent target, but there is reason for hope. First of all both Cristian Maidana and Andrew Wenger should increase their minutes barring injury. Both players spent time in the coaches' doghouse and worked themselves out of it by the end of last season. But the biggest increase in minutes will have to come from the unexpected center back pairing. Ethan White and Steven Vitoria will have to play significantly more minutes than they did last year, and this pairing will be the biggest unknown for the starters going into the season. If those two players earn their minutes, the Union starters will be able to keep the reserves minutes to a comfortable level.

How much will the Union depth have to play?

Looking at the same table for the projected Union reserves reveals something alarming - the Union depth isn't all that bad.

Based on last season's minutes the Union reserves are very close to the 25 percent target number of minutes played. But there are probably a few adjustments we should make. It would be surprising if both Carroll and Casey had the same role this season. The same could be said for Fred, even though he played just 343 minutes. They should all have dramatically reduced minutes played. The good news is that CJ Sapong, Zach Pfeffer and Michael Lahoud figure to absorb those reduced minutes, hopefully without much drop-off in quality.

But there is still one glaring weakness on the Union bench and that is the defensive depth.

When looking at the distribution of bench minutes by team, the Union have significantly fewer minutes played by the defense. With Austin Berry failing to catch on with the Union or the New York Cosmos, the only bench option with any MLS experience is Fabinho.  It appears as though second year player Richie Marquez is waiting in the wings at center back. And of course Maurice Edu would most likely play there if necessary, but that would leave gap at defensive midfield. But from a depth perspective the defensive back line seems the most susceptible to surprises.

It was not that long ago that Union fans had reasonable dreams of a Gaddis/ Carlos Valdes/Edu/Williams back line and were feeling confident. What remains now is a great unknown and roll of the dice by Curtin that White and Vitoria will gel and that there won't be too many injuries to deal with.

Putting it all together

The big unknown in the Union starting XI is how well Ethan White and Steven Vitoria will gel. They will be playing much more than they played all of last season, and how well they hold up to the rigors of a full season will be a key to success.

If you feel confident that Michael Lahoud, CJ Sapong and Zach Pfeffer can all increase their workload than you have little reason to worry about the depth available in the midfield and up top. But no matter what, the Union are thin on defense. If two defenders miss a game to injury or suspension, Curtin will be forced to shuffle the lineup considerably.

And all of this has been said without mentioning the quality of the bench. The Union lacked quality depth last year and yet here we are looking for candidates to hopefully eat up the minutes that remain unaccounted for. The hope of this bench turning into an asset rather than a hindrance for the Union rests on pleasant surprises and players blossoming before our eyes. It appears the Union will be gambling a little bit that their starters won't get hurt all at once. But their gambling a lot that a few players are ready to make a significant contribution to a playoff run.

Do you feel the Union have enough depth? Vote in the poll below.