Caleb Porter, who made his mark at the University of Akron, won the 2015 MLS Cup with Portland. (David Zalubowski/Associated Press)

Caleb Porter’s stunning exit in Portland today marked the seventh MLS head coach to leave his position this calendar year, either by choice or force. He was the third longest-serving boss in the 22-team (soon to be 23-team) league behind Peter Vermes and Ben Olsen. Only five current coaches have guided the same club without interruption for four full seasons.

Here’s the current cast of coaches and the two vacancies …

1. Peter Vermes, Sporting Kansas City (hired in November 2009 after interim role for three months). Status: one MLS Cup title, three U.S. Open Cup trophies, rumored to be in running for U.S. national team job.

2. Ben Olsen, D.C. United (November 2010 after interim role for three months). Status: job is safe despite 20-loss season and last-place finish but needs to make splash at new stadium.

3. Gregg Berhalter, Columbus Crew (November 2013). Status: has led a relocation-jarred club into Eastern Conference finals.

4. Carl Robinson, Vancouver Whitecaps (December 2013). Status: signed long-term extension last fall, finished one point out of first place.

5. Oscar Pareja, FC Dallas (January 2014). Status: bump in the road this season after gaining admirers for style and development.

6. Jim Curtin, Philadelphia Union (September 2014 after interim role for four months). Status: club says he’ll return next season despite missing playoffs.

7. Greg Vanney, Toronto FC (September 2014). Status: overseeing one of the greatest seasons in MLS history.

8. Jesse Marsch, New York Red Bulls (January 2015). Status: sixth place amid youth movement after consecutive first-place finishes.

9. Veljko Paunovic, Chicago Fire (November 2015). Status: oversaw the organization’s renaissance this season.

10. Patrick Vieira, New York City FC (November 2015). Status: Europe down the road but seems happy in Big Apple.

11. Jason Kreis, Orlando City (July 2016). Status: full support from management despite disappointing first complete season.

12. Gerardo Martino, Atlanta United (September 2016). Status: entertaining and successful inaugural season, could draw suitors from abroad.

13. Wilmer Cabrera, Houston Dynamo (October 2016). Status: Revitalized the wayward club, gained Western Conference finals in first season.

14. Brian Schmetzer, Seattle Sounders (November 2016 after interim role for three months). Status: championship last year, championship threat this year.

15. Adrian Heath, Minnesota United (November 2016). Status: decent inaugural campaign, afforded time to grow.

16. Mike Petke, Real Salt Lake (March 2017, replaced Jeff Cassar). Status: the most popular New Yorker in the Wasatch Front.

17. Chris Leitch, San Jose Earthquakes (June 2017, replaced Dominic Kinnear). Status: seems likely to return after earning playoff berth.

18. Sigi Schmid, Los Angeles Galaxy (July 2017, replaced Curt Onalfo). Status: embarking on a major reconstruction project.

19. Bob Bradley, Los Angeles FC (July 2017 for 2018 inaugural season). Status: high-profile coach in a high-profile market.

20. Brad Friedel, New England Revolution (November 2017, replaced Jay Heaps). Status: first pro coaching job after standout playing career.

21. Remi Garde, Montreal Impact (November 2017, replaced Mauro Biello). Status: previously with Lyon and Aston Villa.

22. Colorado Rapids. Vacant. Status: Steve Cooke was the interim coach for most of the 2017 season. Anthony Hudson, the current New Zealand national team boss, is the top candidate, according to multiple sources. An announcement is expected soon.

23. Portland Timbers. Vacant. Status: Caleb Porter left this week after five years, a 68-50-52 regular season record and three playoff appearances. The search for a replacement will commence right away.