Pomeranz was seen with his left shoulder heavily bandaged on Sunday. On Monday, he lasted just 4 1/3 innings and 78 pitches of a loss to the Marlins. Pomeranz (0-4, 8.10 ERA in four starts) insisted Thursday morning that he was not in pain, but the Rockies wanted to wait until after his bullpen session before making a decision about the start.
The Rockies are expected to make an official announcement on Friday.
McHugh, 26, made three appearances, including one start, with the Mets before the trade (0-1, 10.29 ERA). He went 0-4 with a 7.29 ERA in eight games, including four starts, for the Mets last season. His best start came in his Major League debut last Aug. 23 at Citi Field, when he held the Rockies to two hits and struck out nine in seven innings of an eventual 1-0 Rockies victory.
But McHugh spent most of the first part of this season at Las Vegas, where he was 3-2 with a 2.87 ERA before the trade. The Rockies sent him to Double-A Tulsa, where he was 1-1 with a 1.38 ERA in two starts, before bringing him to Colorado Springs, where he went 1-0 with a 3.18 ERA in three starts.
The time between now and when Pomeranz throws his next Major League pitch will give him time to gain confidence. Pomeranz had encouraging work at Colorado Springs, but hasn't made it past 4 1/3 innings in any of his big league starts.
"In my bullpen sessions, I'm just trying to feel comfortable, throw strikes and not get too complicated," Pomeranz said Thursday morning.
Thomas Harding is a reporter for MLB.com. Read his blog, Hardball in the Rockies, and follow him on Twitter @harding_at_mlb. This story was not subject to the approval of Major League Baseball or its clubs.