Sono Kareshi, Kikan Gentei Nitsuki

Chitose Yuzumoto receives a letter telling him to meet the sender in front of the library. He thinks he's waiting for a cute girl, but the person who comes is Riku Hidaka, the ex-captain of the baseball team!! While Chitose tries to hide his shock, Riku asks him to help him make memories for his last year of high school by going out with him for just two weeks. The two start off almost as though they were just really good friends, but soon, Chitose notices some feelings stirring up in him...

(Source: Renta!)