Let's be fair here.
April 21st. DET was tied 3-3 after 5 innings. Coke pitched a flawless 11th inning (2 Ks, 1 infield ground out). He pitched to 4 batters in the 12th, and with 2 outs and none on, gave Pujols an IBB, but retired Hamilton. 2 IP 0 ER 4Ks. He was left in the game, and Trumbo lead off the 13th with a HR. DET loses 4-3 in 13. DET 0-3 with RISP after 5th inning.
April 25th - DET was up 3-2 going to the top of the 8th inning (they last scored in the 5th). DET loses 8-3 in 10 innings. Rondon allowed the tying run in the 8th. After Rondon gave up a hit in the 9th, Coke came on and ended the inning without allowing a run (3 outs, 1 IBB). Coke starts the 10th with an out, followed by double, walk, wild pitch, IBB and then another walk. Again, after starting his 2nd inning of work, at what point does he come out? BTW, he only gave up 1 ER prior to leaving the game. Downs gave up a grand slam to Alex Gordon, resulting in his other 3 earned runs. DET did not have a base runner for the last 5 innings.
June 12th - DET lead 2-0 going into the bottom of the 9th. Both Smyly and Valverde gave up runs, sending it into extra innings. KCR won it with a walk off in the bottom of 10th, winning 3-2. DET offense had not scored in 5 innings. DET went 0-5 with RISP AFTER the 5th inning.
June 27th - DET scored in the 2nd and was a tied game (1-1) after 9 innings. Certainly, Coke got the loss. He had 3 straight hits, followed by a walk. You would think maybe he controls when he comes out of the game. DET went 0-4 with RISP after the 2nd inning. DET lost 3-1.
26 innings in 4 games where the DET offense did not score a run and 0-12 with RISP.
I do not think Coke is the cat's meow, but he doesn't need more blame than he should. At least 3 of these losses where probably because he was left in too long. All four may not have existed if the offense were awake past 6 innings.