Marquis will obviously slide right into Arizona's rotation, taking the slot held for most of the season by Barry Enright, recently demoted to Class AAA. With the D'backs' other four starters all featuring sub-4.00 ERAs, the club should have a consistent (if unspectacular) rotation as they try to catch the Giants down the stretch.
Zach Walters has moved up quickly. Just a ninth-round draft pick just one year ago, Walters batted .302/.338/.440 last summer in the short-season Northwest League, and has fared even better this season in the Class-A Midwest League. Previously a shortstop, Walters has been converted into a utility infielder, seeing time at second base and third base as well as short.
He's been compared to Geoff Blum, which seems strange for a 21-year-old in his second pro season. But there you go.
The Washington Nationals signed Jason Marquis to a two-year, $15 million contract before the 2010 season. He missed much of last year with elbow injuries, but has had a solid season in 2011, posting a 3.95 ERA and 1.41 WHIP in 21 starts, while compiling an 8-5 W/L record. This is very much in line with his career before 2010, when he was a capable fourth/fifth starter for several teams, including the Braves, Cardinals, Cubs and Rockies.
Marquis brings something else to the table; he's a good hitter with a career BA of .199 and five home runs. Teams have also employed him as a pinch-runner, so he can serve as a sort of extra bench player.