(AP Photo/Mark Duncan)

Last season, Carlos Santana hit .268 with 20 homers and 74 RBI. This season, the Indians’ cleanup hitter is hitting 0.158 with a 0.302 slugging percentage through 40 games.

“He’s in a slump,” Cleveland hitting coach Ty Van Burkleo said. “He’s been trying to do a little too much in the games. His work has been great. He just needs to get a couple of hits and get the monkey off his back.”

It’s more than a slump – it is hurting the Indians:

The old-school book says to put your big power bat here, probably a guy with a low batting average, who will hit the big multi-run homeruns.

The Book says the #4 hitter comes to bat in the most important situations out of all nine spots, but is equal in importance to the #2 hole once you consider the #2 guy receives more plate appearances. The cleanup hitter is the best hitter on the team with power.

Right now, the best hitter with power on the Indians is outfielder Michael Brantley. He is third on the team lead in wins above replacement (0.8) and has a .340 on-base percentage with a 0.483 slugging percentage. But Brantley typically bats No. 3, 5 or 6 in the order, meaning fans will have to ride out this Santana slump for a while.

So what’s causing it? A lack of line drives, with more grounders and fly balls.

Last season, 21.8 percent of Santana’s hits were line drives. This season, it’s only 11 percent, mostly because he has yet to hit a line drive off an off-speed pitch (changeups, splitters and screwballs).

In comparison, Santana made just three outs off line drives last season when the pitcher threw an off-speed pitch.

Carlos Santana Hit Spray Chart via Offspeed Pitches 2013

And it isn’t like Santana is seeing more off-speed pitches than normal.

He is just struggling with them right now.

This slump is probably a short-term thing, but until then perhaps Cleveland should let Brantley hit cleanup for a while.