BOSTON - For the first four months of last season, the Red Sox' offense was lifeless. The team hit few homers and seemed unable to generate big innings, both of which were often needed to undo the damage done by the team's own pitching staff.



This season, the Red Sox have been far more proficient offensively. They still aren't among the league leaders in homers -- though that could change before too long, at the rate the Sox are suddenly hitting them - but the Sox rank at the top of the A.L. in a host of categories: doubles, slugging percentage, total bases, on base percentage, and, most importantly, runs scored.



Yet the Sox added no new everyday position players this off-season - platoon outfielder Chris Young was the closest thing to a significant newcomer and he's started just nine of the first 33 games. They didn't change their hitting coach (Chili Davis) or assistant hitting coach (Victor Rodriguez).



So what's different? Let us count the ways.



1) David Ortiz is a force early in the season.



Remember last season? Ortiz probably wishes he didn't.



While Ortiz powers homers and swats doubles at an astounding pace and engenders pleas to change his mind about retirement this fall, it's easy to forget how much of a non-factor he was for the first two and a half months last year.



Well into June, Ortiz was being benched against some lefty starters and principal owner John Henry, in delivering a state-of-the-franchise address in early June, mused about the slugger's declining output.



Then, later in June, something clicked for Ortiz and he began to power the ball, finishing with 37 homers.



This year, he's picked up right where he left off last October. He leads the Red Sox in homers, RBI and slugging percentage, and anchored in his customary cleanup spot, has again become the focal point of the Red Sox offense, changing the way opposing clubs attack the Sox.



That was hardly the case a year ago at this time.



Ortiz on May 11 last season: .243/.332/.411; four homers; 13 RBI.

Ortiz on May 11 this season: .321/.402/.688; nine homers; 29 RBI.



For years, as Ortiz has gone, so go the Red Sox. That's still true in this, his final season.



2) The continuing growth of some young hitters.



In the final two months of last year, the Red Sox started getting significant contributions from Travis Shaw and Jackie Bradley Jr.



Shaw belted 13 homers in the final 65 games, while Bradley enjoyed an August most players can only dream about, with a slash line of .354/.429/.734.



In the first 5 1/2 weeks of this season, Shaw and Bradley continue to rake. Shaw, who enjoyed a six-RBI game Tuesday night, has provided run production from (mostly) the sixth spot in the batting order, having beaten out Pablo Sandoval in spring training to become the everyday third baseman.



Meanwhile, Bradley is second on the Red Sox in both slugging and RBI -- and he's done it from the bottom of the lineup, giving the Red Sox run production from top to bottom while regularly helping to turn the lineup over.



That makes two homegrown players, age 26, who have developed into everyday regulars since late last summer. Clubs dream about that sort of player development influx; the Red Sox are benefitting from it.



3) The Red Sox are using Fenway Park to their benefit.



A year ago, it didn't seem to matter where the Red Sox were. They couldn't hit, home or away. Despite playing in a hitter-friednly ballpark, they couldn't put it to good use until well after the All-Star break.



This year, they're rediscovering the home field advantage.



Take all of the overall categories listed earlier -- doubles, slugging percentage, total bases, on base percentage, runs scored -- and the Sox are No. 1 in the American League at home in those same categories.



In the last seven home games (5-2), the Red Sox have scored 47 runs, or an average of almost nine runs per game.



They may not sustain that for the course of the entire season, but they're fully capable of beating up on teams at home and making Fenway a visiting pitchers' nightmare again.