ST. LOUIS – One of the last things the St. Louis Cardinals can afford is for Jaime Garcia to fall into a rut.

Already, the Cardinals have seen all their other starting pitchers endure multi-start slumps, while Garcia has provided the closest thing to consistency. That run came to a crashing halt Sunday in the Cardinals’ 7-2 loss to the Arizona Diamondbacks.

Garcia (3-4) couldn’t get out of the third inning for the first time in nearly four years, as the Diamondbacks turned his pitches into hit after hit for 10 in all. Garcia’s reliability has been important because veterans Adam Wainwright and Mike Leake are only just emerging from sluggish starts, and Carlos Martinez and Michael Wacha have had a turbulent May.

In a way, it’s a wonder the Cardinals aren’t in worse shape, considering how pedestrian their starting pitching has been. A year ago, this team’s starters had a 3.13 ERA through 44 games. This season, they have a collective 4.24 ERA.

That the Cardinals are two games over .500 is a testament to their relievers and hitters. The bullpen picked up the innings Garcia left out there, but by the time Matt Bowman took the ball, the Cardinals were in a 4-0 hole, and Arizona quickly scored another run on a sacrifice fly.

Jaime Garcia allowed 10 hits and and five runs in just 2 1/3 innings Sunday. Dilip Vishwanat/Getty Images

The hitters couldn’t come to the rescue this time because Zack Greinke (5-3) finally looked like Zack Greinke. The Cy Young runner-up came into the game with a 5.08 ERA, but he held the Cardinals to five hits over eight innings, with the only damage a Brandon Moss solo home run. Greinke is 11-4 in his career against St. Louis.

The Chicago Cubs, who visit St. Louis this week, are the only team in the major leagues with five starters with ERAs of 3.51 or lower. The Cardinals don’t have a single starter with an ERA that good. Garcia’s ERA went from 2.86 to 3.59 with Sunday’s poor outing.

You don’t need to dig much deeper than that to understand why the Cardinals are in such a deep hole in their division.