With Adrian Beltre and Bill Hall, Red Sox Fully Loaded for 2010 Theo Epstein has done a lot to beef up the Red Sox’ roster for next season. He’s added an elite starting pitcher, a top defensive center fielder, and a solid shortstop. The last step was to piece together a bench — and it looks like he’s accomplished a lot on that front too.

With the acquisition of Bill Hall from the Seattle Mariners on Thursday afternoon, it looks like everything’s falling into place for the Boston bench. The Sox surrendered Casey Kotchman, a superfluous power-hitting corner infielder on a team that has several; they received Hall, cash considerations and a player to be named later.

But more importantly, they received comfort in the fact that their roster for 2010 is all set.

Behind the plate, the Red Sox have Jason Varitek to back up Victor Martinez. In the outfield, they’ve got Jeremy Hermida as their fourth guy. At third base, they have Mike Lowell, who’s also prepared to play a little bit at first if the situation warrants.

The last piece of the puzzle was a utility infielder. Dustin Pedroia and Marco Scutaro will be anchoring the middle of the Red Sox’ infield on Opening Day, but they need backups. And in Hall, the Red Sox found a jack of all trades for their infield, a man with major league experience at third base, shortstop, second, left field, center and right. Next thing you know, they’ll have him pitching the seventh inning.

The Red Sox were in need of one more infielder to fill their roster out. Just think of how many able-bodied middle infielders they’ve lost in recent months. They’ve parted ways with Julio Lugo, shipping him to St. Louis this past summer in a salary-dumping move that cut some dead weight. They’ve said goodbye to Alex Gonzalez, who signed with the Blue Jays shortly before Boston poached Scutaro, Toronto’s former starting shortstop. And they’re done with Nick Green, whom they designated for assignment back in November, only to see him flatly refuse to become a free agent.

Among those three guys, that’s over 1,200 innings at shortstop for the 2009 Red Sox being thrown out the window. They were in need of new blood, and they opted for the outside hire with Bill Hall.

The only other choice was Jed Lowrie, and the Red Sox are running out of faith in their 25-year-old shortstop, it appears. Lowrie is in limbo at the moment — he’s no longer a prospect, but not yet a big-league player. He’s been in Boston for parts of two seasons, he’s hit .235 with unremarkable defense, and he hasn’t proven that he’s ready to be an impact player.

Epstein and the Red Sox front office were faced with a choice this winter: give Lowrie the chance to play a full season in the majors for the first time, or look around for a more reliable replacement.

In Hall, they get an adept defender who can take the field anywhere he’s needed and he’s also something of a hitter. His .441 career slugging percentage and six straight seasons with 20-plus doubles makes him American League material. If he can learn to work some counts and take some walks, he’ll fit in perfectly in Boston.

For a guy in the corner of the dugout, effectively a 13th man off the Red Sox’ bench, Bill Hall is a godsend. And with Hall aboard, the Red Sox are now fully loaded and ready for 2010.