Back in 2001, Barry Bonds blasted a record 73 home runs. Sammy Sosa hit 64. Luis Gonzalez hit 57, Alex Rodriguez hit 52, and three others hit 49. All told, 41 players hit 30-plus home runs, and 13 regulars posted an OPS above 1.000.

That's a lot of offense. Now, get this: We're on pace to see more home runs in 2016 than 2001.

Maybe you've noticed this barrage of long balls. The Orioles have a chance to break the single-month total for a team. We're not quite to the halfway point of the season, and 40 players have reached 15 home runs. The White Sox hit seven in a game ... and lost. We've had 32 games already in which a team hit five home runs; in 1991, 25 years ago, that happened just six times.

Two years ago we were worried about the game's offensive decline. The pitchers had become too dominant, strikeout rates were getting higher and higher. In 2014, scoring plummeted to its lowest total since 1981. There was talk about lowering the mound. The pitchers had won.

In less than two seasons, however, the batters have turned things around. Teams are averaging 4.46 runs per game, the most since 2009, and 0.39 runs per game more than two seasons ago. Most of that increase in offense has come from the explosion of home runs. The league is on pace to hit 5,562 home runs, which would be an amazing 1,376 more than in 2014 -- a 32 percent increase -- and would rank as the second-highest season total behind only 2000.

What happened? Let's see where the home runs are coming from. The chart below includes league-wide batting and home run rates against various pitches and different locations in the strike zone:

Two major events helped create the decline in home runs since 2009: The increasing velocity from pitchers and the expansion of the strike zone at the bottom of the knees. It appears hitters have made adjustments, most notably in their batting averages and home run rates against fastballs of 94-plus mph. Home run rates on pitches in the lower third of the strike zone have also increased at a greater rate than pitches in the middle third or upper third.

It's also not surprising to learn that batters are simply hitting more fly balls:

2014: 29.8

2015: 30.2

2016: 30.9

A 1 percent increase in fly balls may not seem like a lot, but that prorates to about a thousand more fly balls in 2016 than 2014. Of course, that's only a small part of the overall home run explosion. Certainly, a new wave of powerful young hitters who were raised on higher velocity and honing their swings for power has been a major component as well. Maybe the pitching hasn't been as good.

With more strikeouts and generally low batting averages, the sport also becomes more self-selective: Home runs are more important because it's more difficult to string hits together, so teams look for power guys. Look at the percentage of runs scored via home runs:

2016: 39.4 percent

2015: 37.4 percent

2014: 33.4 percent

2013: 35.4 percent

2012: 37.0 percent

For comparison, 36.8 percent of runs scored in 2001 came via the home run. But this method still underestimates the extent to which teams now rely on the home run. If we ignore the baserunners and just count the home run hitter himself, we get these rates of runs via the home run:

2016: 25.7 percent

2015: 23.8 percent

2014: 21.1 percent

2013: 23.0 percent

2012: 23.5 percent

2001: 23.5 percent

And there's one more part to this equation. As hitters increasingly sell out for home runs, and teams increasingly sell out for home runs, many of the top home run hitters are simply one-dimensional sluggers. Yes, our list of the current top-10 home run leaders (and ties) includes all-around studs like Nolan Arenado, Kris Bryant and Robinson Cano, but it also includes three players with OBPs under .300 and several designated hitters. Todd Frazier of the White Sox has 21 home runs, but he's hitting .198 and has just five doubles. Khris Davis of the A's has 19 home runs, but 73 strikeouts and just 10 walks. Adam Duvall has been a huge surprise for the Reds with 21 home runs, but with just 12 walks and a .249 average, his OBP is just .284. These players have little value aside from their home runs.

Before jumping to conclusions, I thought I'd compare this year's leading sluggers to the top home run hitters of previous decades. This is by no means a comprehensive study, but I averaged the WAR of the top 10 in home runs for 10-year intervals:

2016: 4.2 (prorated)

2006: 6.1

1996: 6.1

1986: 3.8

1976: 5.2

1966: 6.6

Other than 1986 -- the average WAR that year was brought down by Dave Kingman's minus-1.0 and Dave Parker's 0.2 -- in the previous periods, being one of the top home run hitters also meant you were one of the league's best players.

Six of the top 10 sluggers in 1966 made the Hall of Fame and two others (Dick Allen, Joe Torre) were borderline Hall of Famers (Torre made it as a manager). In 1976, Mike Schmidt, Joe Morgan, Reggie Jackson and Jim Rice were future Hall of Famers, and guys like Graig Nettles, George Foster and Sal Bando were superb all-around players. In 1986, we still had Schmidt, Kirby Puckett, Jesse Barfield and Don Mattingly. Even in 2006, the worst WAR belonged to Jermaine Dye at 4.6. Of the 13 players with at least 19 home runs in 2016, eight project to finish with less than 4 WAR while Trevor Story is currently halfway there at 2.0.

Maybe this is why some of the top home run teams aren't necessarily good teams. Tampa Bay is fourth in the majors in home runs but 25th in runs. The Tigers are eighth in home runs but have still scored fewer runs than the Giants, who have to bat their pitcher and have hit 37 fewer home runs. The Mets are fifth in the NL in home runs, but 13th in runs scored.

Don't get me wrong, home runs are still exciting and obviously valuable. I'm glad offense is up and that hitters are regaining ground. The game can't be just home runs and strikeouts, although the concern is that it continues to trend in that direction. Put it this way: I love diversity of styles and approaches. I want more Jose Altuves and fewer all-or-nothing sluggers.