It’s been a while since the Cardinals and Phillies squared off, but the drought ended tonight, and you can tune in -- for free.

The teams’ series opener at Philadelphia’s Citizens Bank Park (7:05 p.m. ET) is MLB.TV’s Free Game of the Day. (Blackout restrictions apply, although live audio still will be available through MLB.TV in local markets.)

Because teams did not face opponents outside of their region during the shortened 2020 season, St. Louis and Philadelphia haven’t met since May 30, 2019, when the Cards took a 5-3 road win. Much has changed since then. Bryce Harper, then finishing his second month as a Phillie after signing a 13-year contract, has settled into his new home. The Cardinals made back-to-back postseasons in 2019 and ‘20, then went out this past offseason and swung a trade with Colorado for star third baseman Nolan Arenado.

Here is a breakdown of some key things to know before tonight’s MLB.TV stream.

How they’re doing
Cardinals (6-6, 3rd in NL Central)
Phillies (6-6, 2nd in NL East)

The Phillies, looking to snap MLB’s second-longest playoff drought (nine seasons), won their first four games of 2021 but are just 2-6 since, including 1-5 on their just-completed road trip.

The matchup on the mound
Cardinals -- Carlos Martínez (0-2, 6.30 ERA in two starts)
Phillies -- Zach Eflin (0-0, 3.46 ERA in two starts)

Martínez threw arguably the best game of his career against the Phillies on June 10, 2017, in St. Louis. The right-hander struck out 11, walked one and allowed four hits while throwing one of his two career shutouts. His 89 Game Score remains a career high. However, nobody who faced Martínez in that game remains on the Phillies' active roster.

The player to watch
Arenado is always worth keeping an eye on, whether he’s manning the hot corner or has a bat in his hand. The eight-time Gold Glove Award winner -- and four-time Platinum Glove winner as the NL’s best defender -- was traded to the Cardinals on Feb. 1. Arenado was coming off a subpar season by his standards, as he batted only .253/.303/.434 while missing 12 games and dealing with soreness in the A/C joint in his left shoulder. Fully healthy in 2021 and perhaps energized by heading to a contender, Arenado owns a .319/.373/.574 line with three homers and eight RBIs through his first 12 games in red.

His first big Cardinals moment came last Thursday, when Arenado launched a go-ahead two-run homer in the eighth inning to propel St. Louis to a win over Milwaukee and Arenado to a Busch Stadium curtain call.

Don’t forget him
If José Alvarado comes out of the Phillies' bullpen, don’t miss a pitch. The left-hander (99.5 mph) trails only Aroldis Chapman in average fastball velocity across MLB this season and throws some absolutely unhittable pitches. After a tough 2020 with Tampa Bay, Alvarado has been on point in Philly, striking out 10 in 5 2/3 innings.

Picture this
Entering this season, Didi Gregorius had hit 107 home runs since 2015, and 98 of those (91.6%) had been pulled, the highest rate in MLB among 82 hitters with 100 or more big flies. So it was a rare sight on April 6, when Gregorius hit a blast to dead center field against the Mets’ Marcus Stroman. While that homer was further toward left field than any other Gregorius has hit in the past seven seasons, he still has not produced a single opposite-field dinger in that time.

Number of note
Cardinals catcher Yadier Molina just caught his 2,000th career game on Wednesday, becoming only the sixth catcher in MLB history to reach that milestone. He’s the only one on that list to log 2,000 games behind the plate for the same team.