For the last two seasons, Derek Jeter gave people plenty of reason to wonder if he was starting down the backside of the hill that all players have to travel at some point in their careers. A weak year in the field in 2007 was followed by a weak year at the plate in 2008. Injuries helped to explain some of the decline, but that's life for an athlete in his mid-30's and questions about his future effectiveness were justified.
Jeter's answered those questions in resounding fashion. His bat is producing at classic Jeter levels, he's running the bases well and, most surprisingly, his work in the field is as good or better than it ever was. Good health is definitely playing a role in all three facets, but the defensive improvement is the product of more than that and a reason why Jeter is one of the leading contenders for the American League MVP award this season.
Right now, using wins above replacement level courtesy of Fangraphs, Jeter trails only Ben Zobrist of Tampa as the most valuable position player in the league. He is neck and neck with Twins catcher Joe Mauer, with one ahead of the other depending on how they did the night before. Zobrist's candidacy could be hurt by Tampa's regression this season, though, and will definitely be hurt by his status as a super-utility player in his first full big league year. Evan Longoria of Tampa, just behind Jeter, also has to deal with the Rays' slide out of the playoffs (again, if the season ended today) and may be viewed as a guy with plenty of great years ahead of him.
That leaves Jeter and Mauer, each of whom are building a convincing case for the vote. Mauer missed almost all of April, but you wouldn't know it from looking at his production. He's on pace for a third batting title, and catchers always do well in MVP voting because of their perceived importance as a leader on the field. His team is below .500, though, and writers usually give extra credit to players on playoff teams.
There's also the Al Pacino in "Scent of a Woman" effect working in Jeter's favor. Pacino won his first Oscar for that film, even though few film aficionados would rank it among his finest performances. He was overdue for the award, though, and voters were honoring more than just one performance. Jeter has had better seasons than he's having right now, but voters may give weight to the fact that he might never have another MVP-type campaign left in his career. That's not right, but it's human and it could happen.
The writers could also continue their fetishizing of RBIs and give Justin Morneau his second award. It's exactly what happened in 2006, when Jeter finished second in the voting, but writers get even tinglier about a good story than they do about runs batted in. Edge goes to Jeter there, and so could the MVP.