I never completely bought into the idea that the San Francisco Giants were all that interested in Justin Upton or Yoenis Cespedes. For starters, given the Brandon Crawford extension and the Johnny Cueto and Jeff Samardzija signings, the Giants had already committed to a potential $295 million in future dollars. Bringing on another $100 million-plus contract may have been too prohibitive. Secondly, the team needed a center fielder more than a left fielder.

Enter Denard Span, as he agreed to a three-year, $31 million contract with the Giants, pending a physical. That's not necessarily a foregone conclusion as Span played just 61 games last year as he battled hip and core injuries.

If healthy, however, he projects as a two- to three-win upgrade over Angel Pagan, maybe more given Pagan's poor 2015 season when he was worth -1.9 WAR as his defense declined noticeably in center.

Pagan, who had back surgery in 2014, is entering his age-34 season. Here's the list of such full-time center fielders (at least 500 plate appearances and 75 percent of games played in center) over the past decade:

Coco Crisp, 2014
Mike Cameron, 2007-2009
Kenny Lofton, 2006

That's it. You don't see many 34-year-old center fielders. And given the spacious outfield at AT&T Park, quality defense in center field is an important priority.

Of course, Span is no youngster himself as he'll be entering his age-32 season, and his defensive runs saved total last season was -10 runs. He was a little better in 2014 at -3 runs, but the metrics suggest he's no longer the above-average defender he was a few years ago. But he's also an offensive upgrade over Pagan and should slide into the leadoff spot with his .352 career OBP and .358 the past two seasons when he hit .302 and .301. He also fits the Giants' high-contact profile, although he obviously lacks the power of an Upton or Cespedes.

The Giants now have improved outfield depth. Pagan can slide over and share left field with Gregor Blanco, and given that Hunter Pence will be 33 and is coming off his own wrist and oblique injuries, it may be wise to give him an occasional day off after he played every game in 2013 and 2014. It's an old outfield so it comes with all the usual age-related caveats, but Brandon Belt will also play some left field when Buster Posey moves out from behind the plate to play first base. Bruce Bochy is going to love all this flexibility.

Span had not been given a qualifying offer by the Washington Nationals, so the Giants won't lose a draft pick.

This leaves Dexter Fowler and Austin Jackson as the top remaining center fielders. Fowler was given a qualifying offer by the Chicago Cubs, so a team that signs him will lose a pick, perhaps affecting the interest in him. Teams with the lowest OPS from their center fielders in 2015 were (from the bottom): Reds, Rangers, Twins, Astros, Giants, Indians, Cardinals, Braves, Mariners and A's.

Some of those teams have already made upgrades in center or will count on youngsters like Billy Hamilton or Byron Buxton. Fowler would be a good fit with the Cleveland Indians, but they probably don't want to lose their first-round pick. The Nationals are a possibility as well, having lost Span and with Michael Taylor's bat a question mark. The Chicago White Sox are reportedly interested in Cespedes, but only on a three-year deal. They could sign Fowler and move Adam Eaton over to right field.