Key things to watch for in today's games

July is here, and with it comes an opportunity for players to start fresh with a new month, or to show that a previous good month wasn't a fluke. The dog days of summer are when teams try to separate themselves from the pack and head down the home stretch.

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Here are five things to watch for in today's games:

• A tough stretch: BOS @ TOR, 1:07 p.m. ET

Boston right-hander Rick Porcello still hasn't won a game since May 16, and he's taken a loss in all but one of his seven starts since then. He'll try to buck that trend Wednesday against the Blue Jays, who send veteran lefty Mark Buehrle to the mound. Buehrle has had more success lately, allowing just seven earned runs in his last 44 innings.

Video: LAA@OAK: Hahn fans four, holds Angels to one run

• Matinee action in the bay: COL @ OAK, 3:35 p.m. ET

A's righty Jesse Hahn is a fan of day games, having posted a 3-1 record and 1.53 ERA in afternoon contests this year. He'll be up against the Rockies and right-hander Chad Bettis on Wednesday. Bettis has logged at least six innings in two-thirds of his starts this year.

Video: SEA@LAA: Walker gives up one run over seven innings

• Walker winning: SEA @ SD, 3:40 p.m. ET

Young Mariners right-hander Taijuan Walker has rounded into form over his last six starts, going 5-1 with a 1.91 ERA. He's walked just three batters in that span, and none in the last 21 1/3 innings.

Video: ATL@WSH: Fister blanks Braves, helps Nats set record

• Familiar foes: WAS @ ATL, 7:10 p.m. ET

The Braves and Nationals aren't strangers, and the same can be said for their starting pitchers on Wednesday. Nats starter Doug Fister is 4-1 with a 2.18 ERA in his career starts against Atlanta. He'll face off against Matt Wisler, who struggled against Washington in his second career start -- allowing six runs (four earned) on nine hits on Thursday.

Video: CHC@STL: Lackey whiffs five over seven innings

• Sox shuffle: CWS @ STL, 8:15 p.m. ET

Because of a rainout on Saturday, the White Sox shifted their rotation for this week. John Danks was temporarily skipped in favor of Jose Quintana, who is seeking his first victory since June 10. The Cardinals made a few changes, too, with John Lackey pitching on regular rest despite a Monday off-day because of Jaime Garcia's groin injury.