ST. LOUIS -- The Pirates have made a pair of additions to their roster, signing outfielder Jake Marisnick and catcher Andrew Knapp?.

Knapp was seen at Busch Stadium on Wednesday taking batting practice for Pittsburgh ahead of Thursday's Opening Day matchup with the Cardinals.

The signing of Marisnick, in particular, comes in the wake of outfielders Greg Allen and Anthony Alford catching the injury bug.

Allen was the clear front-runner to be the Pirates¡¯ Opening Day right fielder, but he experienced left hamstring discomfort when sliding into home on March 31 against the Orioles and was placed on the 60-day injured list Thursday.

Alford was in line to be the Pirates¡¯ fourth outfielder, but he aggravated his right hand during live batting practice and was placed on the 10-day injured list, retroactive to Monday. He had experienced tolerable pain in his right hand throughout the spring but was able to play through it until the live batting practice session.

Marisnick, who was released by the Rangers on Tuesday, has one calling card: elite defense. Though a below-league average hitter by OPS+ (35 in 2021), Marisnick has been one of the game¡¯s best defensive outfielders since debuting in 2013, accumulating 75 defensive runs saved in that span, eighth most among outfielders.

The 31-year-old has primarily been a center fielder during his career, having played 601 of 722 career games at the spot. Of the two corner outfield positions, Marisnick has spent about the same amount of innings in left field (410) as right (393 1/3). By defensive runs saved, Marisnick grades out better in left (14) than right (9).

Marisnick provides speed as well, having swiped 77 bases in 105 attempts (73.3% success rate). In 2021, Marisnick's sprint speed ranked in the 90th percentile, per Statcast.

The signing of Marisnick provides clarity as to how the Pirates¡¯ lineup will look come Opening Day. He'll likely be penciled in for right field, which would allow Cole Tucker -- who has been working in the infield and in the outfield -- to shift to second base.

When Pittsburgh assigned both Michael Perez and Jamie Ritchie to the Minors, the club was left without a backup catcher. Knapp fills that vacancy.

Knapp, who backed up J.T. Realmuto in Philadelphia the past three seasons, signed a Minor League deal with the Reds in December before being released on Sunday. He does not grade well by defensive runs saved (-30 across 1,652 career innings), but he earned staying power with the Phillies for his ability to develop rapport with the pitching staff. That trait will be valuable given the collective inexperience of the Pirates¡¯ staff.