For the season, the 38-year-old has 14 saves with a 6.85 ERA, and opponents are hitting .308 against him.
"Rodney has struggled a little bit," McClendon said. "So has everybody else. But the fact is, he's our closer. We need him. We're going to need him to be successful. People talk very lightly about changing closers, and that's fine. But you have to have somebody to do it. You don't just throw anybody in the ninth inning and say, 'Well, let him do it.'"
Rookie right-hander Carson Smith has put up a 1.17 ERA in 24 appearances as a setup man, but the Mariners have picked his spots primarily against right-handed batters. Thus McClendon said Smith is not as obvious a solution as some want to believe.
"I don't have that guy right now," McClendon said of alternatives. "I know people point to Carson Smith, but he's a young kid. We have to be careful with him, particularly with his innings and back-to-back-to-back [appearances]. I'm not sure he can do that. I think his velocity goes down quite a bit. He's one of those young men that still doesn't have his man muscles, so to speak. He needs to mature and continue to develop.
"He's doing a nice job, and part of that is we're putting him in situations to be successful. When you're a closer, you don't have that comfortability where we can put you in situations where you can be successful. It is what it is and you've got to go in there and get it done."
McClendon said Danny Farquhar is a guy with closer potential and he filled that role in the second half of 2013 for Seattle, but Farquhar has struggled this year and is currently in Triple-A Tacoma, where he threw 3 2/3 innings in a starting role on Tuesday in an attempt to get squared away.
"His stuff was sharp," McClendon said of Farquhar's two-run outing. "He tired a little bit, but that's OK. The thing we're trying to do is just get him out there, get him some innings and get him sharp again. Because you talk about an option at the big league level, he's an option, but he's not here."
McClendon indicated Farquhar likely would get another similar long outing or two in Tacoma to let him work on some specific pitches.
"We'll see," said McClendon. "I'd like to get him stretched out a little more, get him a few more innings and then get him back here at some point."