Domonic Brown, 2013
You knew it was coming.
A 20th-round selection by the Phils in 2006, Brown performed well all throughout the minor league system, generating some real hype before he even arrived in the majors. The Phillies became so enamored with him that they reportedly wouldn't even consider including him in a trade for Roy Halladay.
Finally, in 2010, Brown arrived in the bigs, playing in a reserve role down the stretch for that powerhouse club which somehow fizzled out in the NLCS. 2011 would be Brown's first real shot, but fate had other ideas, as he broke his wrist in spring training. It sapped his power almost entirely, and he only appeared in 56 games that year. In 2012, a variety of other injuries limited him to 56 games with the Phillies once again. Hope was starting to flag, but 2013 would be a different story.
Finally healthy and given a starting role right out of the gate, Brown had a so-so April, but he became otherworldly in May. Across 28 games, he collected 12 home runs and 25 RBI to earn two NL Player of the Week awards and NL Player of the Month honors. If you expand this timeframe to include the tail end of April and the first week of June, Brown had a 39-game stretch where he hit .325 with 17 home runs and 39 RBI.
It was, quite simply, one of the greatest six-week heaters in team history, and Brown ended up being selected as an All-Star. By the time the Midsummer Classic hit, however, Brown had already slowed down notably. And following the break, he was downright dismal. He put up a respectable .270 average the rest of the way, but he collected just four home runs and 16 RBI over 44 games in the second half while battling more injuries. His final line of 27 home runs and 83 RBI was extremely disappointing, considering how good he had been for a quarter of the season.
Brown's struggles continued in 2014, as he appeared in a career-high 144 games but hit just .235 with 10 home runs and 63 RBI. In a last-ditch effort to get him going, the Phillies started Brown in the minors in 2015, but it made little difference when he came back up, as he hit just .228 over 63 games with five home runs. He was dropped from the club at the end of the season, and he never made it back to the majors.
It's also notable that Brown had the most ridiculous but appropriate end to a career in Philadelphia sports history, as he misplayed a bloop down the line into an inside-the-park home run by flying into the stands and suffering an injury/sheer embarrassment that kept him from ever appearing in another MLB game. Incidentally, this happened in Aaron Nola's ninth career start, making it seem both forever ago and somehow still tangentially related to the current team.
We are all still shaking our heads.