This season, the Chicago Cubs’ pitching staff has kept them in the playoff race. Their top three pitchers of Jon Lester, Jake Arrieta and Jason Hammel have been excellent, but there’s been a marked drop off after that trio.

Kyle Hendricks has been great at times, but is also wildly inconsistent as the No. 4 starter. Meanwhile, the No. 5 starter spot has been a revolving door.

It was Travis Wood’s job out of Spring Training, but he floundered, forcing Tsuyoshi Wada into the role. Wada has been on the DL over the past couple of weeks, which has forced a number of different starters into spot-start duty.

Clayton Richard, who has been one of those starters, hasn’t been getting the job done. His latest outing saw him allow three earned runs in 5.2 innings, including two home runs. It wasn’t his worst start, but his inability to work through an opposing lineup three times in a game has made it painfully obvious that the Cubs need to add another starting pitcher to improve their chances at making the playoffs this season.

After all, the Cubs’ offense hasn’t been hitting well over the last month or so, so they need all the help they can get from the starting rotation. Here are some middle-of-the-rotation pitchers the Cubs could pursue in the next week or so:

• LHP Scott Kazmir
• RHP Mat Latos
• RHP Tyson Ross
• RHP Mike Leake

Any of those starters would be an instant upgrade in the middle of the rotation. Depth is the name of the game in the starting rotation down the stretch as teams have to be able to roll over the rotation and limit losing streaks while maximizing winning streaks.

It has been obvious for a while now, but with Richard’s latest outing, it is clearer now more than ever that the Cubs need to add another starting pitcher to the fold. If they don’t, they might have to wait until 2016 to contend for a playoff spot.