Unlike a lot of newspaper writers, talk show ranters and blogosphere analysts, I refused to criticize the Mariners’ decision to keep Brandon Morrow in the big leagues while they converted him from reliever to starter. The new regime, from GM Jack Zduriencik to manager Don Wakamatsu and his staff, has done so much right with this club that I wasn’t about to say they were wrong with Morrow until they gave it a chance.

Sure, he was bound to have command issues with the fastball and experience days when the curve and changeup felt like a cotton ball coming out of his hand. Sure, it would be easier to let him deal with those issues at the minor league level.

But at the time of the conversion, there didn’t seem like a better alternative than to run Morrow to the mound every five days in the big leagues. Erik Bedard couldn’t pitch because of a sore shoulder and Ryan Rowland-Smith remained erratic at Class AAA Tacoma in his comeback from an arm problem.

As long as Morrow made progress and wasn’t responsible for burning down the bullpen in every start, that’s all anybody should ask. Then he went out every fifth day and strung together a series of starts that don’t look like progress. He has gotten past the fifth inning only once and, tonight in a 6-4 loss to the Rangers, was so erratic with his command that Wakamatsu said there was no choice but to pull him after five.

Have we reached a point when it’s time for Morrow to continue his work at Tacoma? Probably.

Morrow’s performance tonight revealed more than inconsistent command. Postgame comments from Wakamatsu and Morrow make you wonder if, one, he has the secondary pitches needed to compete at this level and, two, if he’s on the same page with his skipper and his catcher (Kenji Johjima tonight).

Wakamatsu said Morrow didn’t have a feel for his curveball tonight, which is a must against a heavy-hitting team like the Rangers. Morrow seemed surprised when asked about it, saying he didn’t throw a curve all night because Johjima didn’t call for it and he didn’t shake off his catcher all night. That sounds like a guy who needs a better understanding of pitch selection and sequences, which he also can learn better at the minor league level.

Whatever.

Bottom line is Morrow has more developing to do and the Mariners are in a position now to let it happen at Tacoma. They won’t need five starters until July 25, and even then they can bring left-hander Jason Vargas back (he was optioned to Tacoma this week) or call up Rowland-Smith (who has a 2.13 ERA in his past two starts and pitched 7 1/3 innings Tuesday at Salt Lake).

Left-hander Garrett Olson, who started while Bedard was out, is another option although he has pitched impressively out of the bullpen, especially in left-on-left situations.

The first half of this season, the Mariners spent a lot of time determining, in Wakamatsu’s words, “what we have” in their young players. We’re in the second half now and if the Mariners are in this to win it, they’re hurting themselves by letting Morrow learn by absorbing the knocks he’s taking at this level. The Mariners aren’t winning when Morrow pitches; Friday was his first loss in six starts, but the team is 1-5 in those games.

There’s no doubt Morrow has electric stuff, but the time is right to let it develop at a place where both he and the Mariners will benefit most — Tacoma.