Fielder's replacement at first base just couldn't do it anymore.
Moreland will miss about three months for surgery on an ankle that's been bothering him all season. The timing could mean that he's finished for the year, just as Fielder is after neck surgery late last month.
''I felt like I was obligated to the team to go out there and give it what I had,'' Moreland said Sunday. ''I felt like I did that for the most part until it came to a point where I can't do it.''
The 28-year-old Moreland had two injections to ease the pain, and he said the most recent shot lasted about five days. He finally went to manager Ron Washington to say the pain was just too strong.
''It's to the point where I'm hurting the team, hurting myself trying to go out there and make something happen,'' said Moreland, who knew surgery was coming but wanted to wait until the offseason. ''It's hurting pretty bad.''
The Rangers, who didn't plan an immediate roster move Sunday, lead the majors in both disabled list uses with 18 and current players on the DL at 12. Moreland will become the 13th once they decide what to do about first base. Utilityman Donnie Murphy started Sunday against Cleveland.
''It's hard to put your finger on it,'' general manager Jon Daniels said. ''It's been a little bit everything - ankles, backs, necks, elbows, legs, shin bones. We haven't been able to connect the dots.''
Fielder, acquired in an offseason trade that sent popular second baseman Ian Kinsler to Detroit, was supposed to restore some power to an offense that dipped significantly in 2013.
But Fielder hit just three home runs in 150 at-bats before acknowledging that he was dealing with neck pain that even went back to last season. He had surgery to fuse two disks in his neck.
Moreland had a career-high 23 homers last year while hitting just .232. But he has gone deep just twice in 167 at-bats this year and is hitting .246.
''He's done everything he could have done,'' Daniels said. ''He's fought through it, but it's become apparent it's limiting him.''
Catcher Chris Gimenez, who has given the Rangers a surprising boost with his bat, has limited experience at first base in the majors and could be an option when the Rangers make a move, likely later Sunday or Monday.
Another possibility is Jim Adduci, who played first early in the season but has been out since April with a broken finger on his left hand. He was close to returning when he injured the same finger during a minor league rehab assignment Saturday.
''We're just going to have to go with what we've got,'' Washington said. ''I'm just trying to make the guys I do have believe they can and just go to war. That's it.''