The Los Angeles Angels, who are actively pursuing a starting pitcher, had a scout watching Miami Marlins right-hander Josh Johnson on Monday night.

That doesn’t mean, however, that Johnson is their top priority - not when Milwaukee Brewers right-hander Zack Greinke and Tampa Bays righty James Shields also are available in trades.

Johnson, 28, is a top-of-the-rotation starter when healthy, but his only season of more than 30 starts and 200 innings was 2009. He also is earning $13.75 million both this season and next.

Shields, 30, likely would be more appealing to the Angels for several reasons.

He is from Southern California. He is experienced in both AL East and postseason competition. And he is more affordable than Johnson, earning $7 million this season with a $9 million club option for 2013 and a $12 million club option for ’14.

Greinke, a potential free agent, is the wild card.

He is the biggest potential difference-maker. As a potential free agent, he likely would come with a lower acquisition cost than Shields. But if the Philadelphia Phillies re-sign left-hander Cole Hamels, the demand for Greinke might only rise.

And then interested teams would face a choice:

Do they gamble on a rental?

Greinke, 28, would be a potential long-term replacement for the Angels if they decline club options on right-hander Dan Haren and/or righty Ervin Santana.

If Greinke left after being traded in the middle of a season, the Angels would not receive draft-pick compensation under the new collective-bargaining agreement.

The Angels surely are looking at other starting pitchers as well, as are their principal rivals, the Texas Rangers.

The competition between the two clubs will be one of the more intriguing storylines leading to the non-waiver deadline next Tuesday at 4 p.m. ET.

-Ken Rosenthal