Before the days of ubiquitous online video, tracking progress of an American playing abroad meant interpreting match reports and speculating on second-hand information.  This was especially true of players in the youth team, as few actually watched these games.  In place of YouTube, transitive property: if a player was at a Euro club, and that Euro club was good, it stood to reason that the player had national team potential.
For years, John O’Brien was “that guy at Ajax“.

O’Brien made his US debut against Austria in April 1998, likely the first glimpse of his play for US fans.  He entered as a late sub for Frankie Hejduk – a symbolic yin and yang of the national team – but injuries precluded O’Brien from becoming a fixture of the team until 2001.
O’Brien timed his emergence well, though, and provided the US with another catalyst in midfield through the final stages of World Cup Qualifying.  Earnie Stewart provided insight on O’Brien’s skill:
“There’s always a lack of those players, no matter where you are in the world.  John is not afraid of receiving the ball and distributing the ball.  He’s always in the right place at the right time.  Most importantly he has the ability to slow the game down. Claudio is the same type of player.”
In the 2002 World Cup, O’Brien cemented his reputation as a technically gifted player with a goal against Portugal and a tremendous assist on Clint Mathis’ goal against South Korea.  Alongside Claudio Reyna and Pablo Mastroeni, O’Brien provided the US with an unprecedented balance of skill and steel in the center of midfield.
Sadly, O’Brien’s international career peaked with this tournament.  He battled injuries the following club season, but displayed resilience and returned to play both legs of the Champions League semi-finals against AC Milan.  O’Brien made a brief resurgence at the 2005 Gold Cup, scoring in the semi-finals, but spent most of 2005 and 2006 hurt.  O’Brien’s unique talent earned him a 2006 World Cup roster spot despite lacking full fitness, but his career ended after a 45 minute appearance against the Czech Republic.
O’Brien’s career consisted of a mere 32 caps and 86 professional appearances, but his ethereal quality still captures the imagination of US fans.  Few have approached the technique level and tactical flexibility of O’Brien in his prime.  The open questions are what level did O’Brien reach, and could others replicate his path?
I analyzed O’Brien’s career trajectory on three simple but crucial variables:
1) How often did he play?
2) In what capacity did he play?
3) How good was the team?
Why use these three variables?  The first is fundamental: a player does not improve without eventually seeing the field.  The second discerns if the player is starting or coming off the bench.  The third serves as a skill level litmus test, as better teams have better players.
For metrics, we’ll start with minutes played in a league season.  Then, we look at total appearances and multiply by 90 to calculate the total possible minutes of action – a higher percentage is more likely for starters.  For team strength, we’ll once again use ClubELO’s database and the team’s ELO score at the beginning of each season.  Lastly, total minutes in a league season are weighted across a team’s ELO score.  This serves as a proxy for a player’s contribution to a team’s success.
Here is O’Brien’s chart, using data from Transfermarkt:
John OBrien ELO Career 11-18-15
The light blue bar (“Contribution”) is minutes played as a percentage of total league minutes.  The dark blue bar (“Max Contribution”) is the total possible minutes based on the number of appearances a player made.  The gray bar (“ELO Score”) is total league minutes.
His first year at Ajax featured 11 starts in 16 appearances.  The 1,097 minutes O’Brien played totaled 36% of the total league minutes and 76% of possible minutes from those 16 appearances.  His best season was the 2001/2 campaign, where his 2,182 minutes equated to 71% of the league total when Ajax won the league and league cup.
It’s well-known that O’Brien was the epitome of injury-plagued, but what’s remarkable about his career is that he continually returned as a starter.  Even when Ajax improved from 1600 ELO in 2000 to 1779 ELO in 2003 – a rise from outside the top 100 teams in Europe to one of the top 25 teams –  O’Brien’s contribution rate remained in the 90% range.
What I like about this type of analysis is it can be used as a first filter to assess players across positions and leagues.  We determined O’Brien succeeded when healthy, so how can others follow his path to the national team?
For Euro-based players, we can simply follow this same analysis, and even for players in leagues without ELO scores like MLS or Liga MX, minutes played and contribution rate still indicates quality.  As a rule of thumb, when a player reaches a 90% of available minutes and 70% of total league minutes, he’s ready for shot at the next level, whatever that may be.  A recent analysis from 21st Club shows if a player appears in 70% of the possible minutes in a season, he is among the top 5 players appearing for the team.
The final variable in emulating O’Brien’s path is age.  O’Brien joined Ajax as a youth player, and made his debut with the club at 21.  There’s no guarantee that player will make it with a European club, but development is viewed differently by prospective clubs and the national team if a player reaches that 90% contribution rate at 22 or 25.  Alex Ferguson categorized a player’s development stage as younger than 23.  For example, Darlington Nagbe hit the 90%/70% benchmark at age 22 in his second season with Portland.  Lee Nguyen reached the threshold at age 26 in 2013 with New England.  The difference is essentially a full World Cup cycle, and makes O’Brien’s achievement stand out even further.