As Major League Soccer's second season winds down, D.C. United Coach Bruce Arena has gotten increasingly frustrated by the young league's growing pains.

In his most candid and critical remarks about MLS since leaving the University of Virginia two years ago to guide United, Arena said: "The way our league is operating, this is one of the worst coaching jobs in the world, in MLS. There's so much you don't have control over. It's a young league in terms of not only our development on the field, but off the field."

Arena has been calling for changes in the way the league operates. An increase in each team's roster -- currently at 20 players -- is necessary, he says, to have enough rested players for league games and other competitions, such as the U.S. Open Cup and the CONCACAF Champions Cup, a tournament to determine the best pro team from North and Central America and the Caribbean.

Both events occurred this year during the MLS season. As a result, United recently had a brutal stretch in which it played 13 games in 36 days.

"It's such a mess, and the coaches are really painted into a corner sometimes," Arena said. "But that's something that obviously you would like to believe, as we move along, is going to be better. We need to have the right roster sizes, the right scheduling. We need fixture dates for Open Cups and other competitions. We need clarity on the salary cap, player movement, a lot of things. Once you are able to understand that going into the season you have better control of how you organize your team."

MLS Commissioner Doug Logan responded to Arena's comments by saying: "He, above all other coaches, is aware of the difficulties inherent in scheduling and organizing this young league. This year he has chosen to make several intemperate remarks about the U.S. Soccer Federation and MLS. He and his team would be better served by him focusing on his job, or sending me his resume. He frequently only opens his mouth to lace his shoes."

The pressure on MLS coaches, Arena says, is extreme and has resulted in unjustified dismissals. Only three coaches -- Arena, Dallas's Dave Dir and Kansas City's Ron Newman -- are with the team with which they started during MLS's inaugural season last year.

"It's no secret why many coaches in this league have lost jobs," Arena said. "In some cases, it was the wrong people being faulted. I haven't seen anyone in the league office buy it or any general managers buy it."

Arena also criticized the league for allowing the struggling New York/New Jersey MetroStars to add a high-priced star -- Brazilian defender Branco -- late in the regular season apparently without any regard to the salary cap. "It's a disgrace," Arena said. "You're not getting rewarded for being good, you're rewarded for being bad."

Arena's comments come near the end of a very successful but difficult season for United (19-9). Injuries, national team obligations or indoor soccer conflicts have cost United a combined 65 man-games from defender Mario Gori, goalkeeper Mark Simpson, midfielder Marco Etcheverry and forwards Jaime Moreno and Raul Diaz Arce. Last month Gori and Diaz Arce were arrested -- and later indicted by a grand jury -- for allegedly raping a 24-year-old woman in a Columbus, Ohio, hotel room following a United match. They pleaded not guilty, are free on $500,000 bond and are awaiting a trial date.

Nonetheless, United has reestablished itself as the favorite to win the league championship again.

"It's something I personally never want to experience again," Arena said about the hectic schedule and other distractions. "I'm sure I never want to play a season like this again." CAPTION: MLS Commissioner Doug Logan, above, on Bruce Arena: "He frequently only opens his mouth to lace his shoes." CAPTION: United's Bruce Arena says 2-year-old league is "such a mess" and coaches are "painted into a corner sometimes."