WASHINGTON — Struggling Pittsburgh Pirates left-hander Jonathon Niese will try to get on track in the bullpen after being removed from the starting rotation.

Pirates manager Clint Hurdle announced the decision to demote Niese to the bullpen on Friday before the team opened a three-game series at the Washington Nationals. Niese is 7-6 with a 5.13 ERA in 18 starts this season after Pittsburgh acquired him from the New York Mets for second baseman Neil Walker.

“We felt at this time to get him unplugged, to get a different look might help him moving forward,” Hurdle said. “We told him this wasn’t a banishment out of the rotation for good. We’re just unplugging him, putting him in the bullpen for right now, see where that can take us.”

Niese has allowed 20 home runs, struck out 71 and walked 36 in 101 2/3 innings. The groundball pitcher allowed 20 home runs all last season and is two away from tying a career high.

The 29-year-old said he understood the decision but didn’t expect it.

“I’d rather start obviously. It’s where my heart’s at,” Niese said. “I knew the rotation was getting pretty crowded. ... I knew something was going to happen. I was certainly hoping it wasn’t me to get bumped. It is what it is. I understand the results weren’t there in the first half.”

During a radio appearance Friday morning, Pirates general manager Neal Huntington said in hindsight that taking two “fringe” prospects from the Mets might have been a better return for Walker than Niese, who has not worked out as planned.

“Given the thinness of the starting pitching market, given the dollars that we had available, we felt that that was our best return and it has not played out that way and that’s a challenge,” Huntington said on 93.7 The Fan in Pittsburgh. “We own that. We accept that.”