West Ham boss David Moyes says they're still learning about handling European commitments.
West Ham face Silkeborg in the Conference League tonight.
Moyes said, "I don't know if we have mastered playing Thursday-Sunday, and actually I don't know if teams have got over it, if I'm being honest.
"We did master it in as much as we won the group last year and we got ourselves in a really good position, but I think when it came to the quarter-finals and the semi-finals, we had home and away ties in the knockout stages and we were in an important period in the Premier League.
"If you get through here, it's March before you play again [in the round of 16], so then if you're good enough to get through, you have the quarter-finals and semi-finals in a period of the season in the Premier League when you have to play all of your [first-choice] players in all of the games, when in the early round you can change five or six players in each game and they don't have to play every Thursday-Sunday.
"When you get to those latter stages, you have to play nearly your best team and that means it has an effect [in the Premier League], and it did have an effect on us last year.
"I think we've done it quite well and I'm pleased about that, but we strengthened the squad partly because I felt that probably, come February or March last year, we didn't really have the numbers to cope with the games we had.
"I think the Thursday-Sunday thing, there is a psychological thing about it.
"But I definitely think that the lack of recovery time, getting ready, and the lack of preparation time between the game on a Thursday and the next game on a Sunday, you have to think that you're not away from the stadium until midnight after most Thursday games, and if you're away from home and having to travel back, at best you have a day to try and get yourself ready for the next game. And to be prepared for the Premier League games, that's really difficult.
"We have got Manchester United away in the Premier League on Sunday and I have to think about both scenarios. But let's be fair, I've thought about them in all the games.
"The next game is always the most important and our next game is Silkeborg and that is the most important game for reasons which that have already been mentioned. But we've also got to consider other things, we have to keep the players fresh and ready for the level of games we've got coming up."
