"The player has MET his fans expectation(s)." "Fans" does not require an apostrophe because it can be interpreted as an adjective (although it is not an error to use an apostrophe). Similarly, you would talk about "the home team" rather than "the home's team". Your second sentence does not sound good. Say "The player's performance has risen to meet (or 'match') fans expectations" or "The player's performance now matches his fans expectations" Your third line ("A player joined...") is correct. However, the plural, "expectations", works better than the singular. Use the singular to talk about a very specific expectation: "Fans had an expectation that he would achieve a new home run record." Fourth group: "As a new member of the club, the player performed badly. However, he has since improved. He has finally reached that level where fans feel satisfied. " (I like "that level" better than "a level" because it emphasizes that he has reached that particular level of achievement.)