Actually, maybe so. Palmer puts up big yardage totals at times, but at the cost of too many interceptions. But it's up to you whether you want to pull the trigger now or wait a week. In his matchup against the Steelers on Sunday, there's certainly room for Palmer to pick up some fantasy points, particularly cheap ones if the Steelers jump out to an early lead. Palmer racked up 248 yards and two touchdowns in his last matchup against the Steelers, who have allowed several opposing quarterbacks this year to have big fantasy weeks (Tom Brady) or at least decent ones (Drew Brees, Ryan Fitzpatrick, Chad Henne). Be aware, though, that you're taking a risk, as there's certainly the potential for the Steelers to rack up turnovers and sacks.
After that, though, Palmer's schedule looks pretty bleak. After the Steelers matchup, Palmer's remaining three games include one against a team that's good at defending the pass (the Baltimore Ravens) and another against a team that's downright lethal to opposing quarterbacks (the San Diego Chargers). His other matchup against the Cleveland Browns is a bit easier, but not spectacularly so.
The top two players on ESPN's most-added list, Jay Cutler and Matt Cassel, have tough matchups this week (and Cassel also might not play) but might be good adds after this week. Jon Kitna is also a good pickup if you just need a guy for a week or two. Consider keeping Palmer for a week, then reevaluating. He may not be worth the roster spot by this time next week.