Tim Howard hasn't made a decision on 2018 World Cup

Tim Howard has been a part of the United States team since 2002 and their starting goalkeeper since 2007, but at 35 years old, he knows that his time is coming to an end. The question is when, and whether he wants to give it another cycle so he can play at the 2018 World Cup.

As of now, he doesn't know.

"I'm pretty good with doors opening and closing, always have been," Howard told ESPN. "It's so hard to talk about four years from now because maybe I'll feel differently then than I do now. I've played enough games; I just try to focus on the next one. I'm trying to compartmentalize. Everything else I don't really concern myself with."

Howard signed a new contract with Everton last month, which runs through the 2017-18 season and he said that he plans on that being his last one. But if he is going to retire in 2018, he can do so after the World Cup, going out with one last season for Everton and one last World Cup. The question is whether he wants to.

Playing internationally, especially for the U.S., is a huge added toll on the body. Instead of summers off or breaks throughout the season during international breaks, Howard has had to travel across the Atlantic repeatedly and play matches. For an aging player, that travel and those matches add up, especially when the alternative is rest and relaxation. International retirement has allowed Brad Friedel to play well into his 40's and while Howard has said he doesn't want to play that long, it could make it easier for him to play at a high level until he decides to hang it up.

Of course, there is no guarantee that Howard will even be the starter in four years, even if he does choose to continue playing for the U.S. Brad Guzan has been excellent and, at least at the club level, arguably better than Howard. If Howard's form dips at all as he ages, or even if it doesn't, he could very easily end up Guzan's backup before long.

The good news is that even if Howard decides to retire, the Americans have a plenty good goalkeeper to take over in Guzan.

It would be unusual for a player to start a new cycle and decide to retire halfway through -- at least barring injury -- so odds are that Howard will make a decision on the next four years between the end of the World Cup and the end of 2014. That means this World Cup could be the last time Howard puts on a U.S. shirt, not that he's thinking about that ... yet.