Josh Willingham is coming off the worst full season of his career. It's very easy to say that this was due to a 34 year old player reaching his inevitable decline. But is it really that simple? I wanted to take a deeper look at the numbers to see if this was the case.

Willingham actually started his 2013 campaign off well. He continued where he had left off in 2012. Josh posted a .250/.400/.544 slash line in April. Unfortunately, that would be the only month where he was above league average at the plate. What happened?

On April 27 the Twins were playing a home game against the Texas Rangers. In that game, Willingham thought he'd show off his wheels and steal second base. It was a success! The Hammer had stolen his first base of the season. Unfortunately, in that moment of glory, Josh awkwardly slid into second base and injured his knee.

At the time, it didn't seem to be too serious. However, it became increasingly clear that something wasn't right. Willingham continued to play the next two months. Between April 27 and June 30 he posted a slash line of .214/.342/.353. The decision was finally made for Josh to have surgery.

On August 9 Willingham rushed back to his team and made his return to the lineup. Like the good teammate that he is, he came back ahead of schedule. Unfortunately, he was not rewarded for it. After his return Pedro Flo.. I mean Willingham finished the season hitting .182/.318/.315.

Did Willingham really decline that much? Did he go from being a power hitting outfielder to a light hitting middle infielder?

Let's take a look at some secondary numbers, to really evaluate whether his regression was due to decline or more injury related.

2013 Career

LD%: 18.3 19.0

GB%: 36.5 36.9

FB%: 45.2 44.1

IFFB%: 17.6 12.8

HR/FB: 11.8 15.1

As you can see. Other than hitting more infield pop ups and his HR to FB ratio dropping, everything else is in line with his career numbers.

Now, let's take a look at his plate discipline. This will compare his approach in 2013 to his career year in 2012.

2012 2013

BB%: 12.4 14.0

K%: 22.9 27.2

O-Sw%: 21.7 21.5

Z-SW%: 62.7 59.8

SW%: 40.4 38.6

SwStr%: 9.5 10.3

Just in case you aren't aware. O-Sw% is the percentage of pitches the batter swings at outside the strike zone. Z-Sw% is the percentage of pitches the batter swings at inside the strike zone. Sw% is the total percentage of pitches a batter swings at. SwStr% is the batter's swinging strike percentage.

It looks like Josh took a more patient approach. Swinging at less pitches. Which helps explain his increase in walk and strike out rates. The increase in SwStr% is a little worrisome, but it isn't a big enough jump to worry too much about. The big thing to me is that his O-Sw% was the same. Meaning he wasn't chasing bad pitches. For a comparison, Oswaldo Arcia had a 37.3 O-Sw% in 2013.

All in all, I see very little that tells me Willingham was a much different hitter in 2013. He got on base, he struck out and he hit fly balls. The thing that went missing was his power. However, his power outage seemed to correlate with his knee injury.

Is it fair to think that Willingham's early season .944 OPS would have come down to earth? Of course. I think it's also fair to think that the injury, along with rushing back from it, were the main reasons for his horrible 2013. If the Hammer shows up healthy in 2014, I think his career .830 OPS is a reasonable projection.

Let's just hope he doesn't go Darin Mastroianni on us again.