Sen. John McCain is calling Sarah Palin an "outstanding candidate" for the Republican presidential nomination in 2012, but says it's too early to endorse her.

McCain told CBS's "The Early Show" Tuesday that "I don't think Sarah would want me to, before she's even able to make a decision" about running.

The Arizona Republican said "it's very early to start picking winners and losers." He said he still holds his 2008 running mate "in high regard" and said he's been amused by the former Alaska governor's confrontations with "the liberal media."

Palin has been active in the campaign, raising money, throwing her support behind a host of tea party-backed conservative Republicans and giving speeches around the country.