The Pittsburgh Pirates are running out of outfielders, but it is not stopping them from winning. The Pirates hope to have at least one of their injured starters back when they attempt to push their winning streak to five straight games and sweep the series from visiting St. Louis on Sunday night. Andrew McCutchen was already out when Starling Marte hurt his back sprinting out a grounder on Saturday, forcing Gaby Sanchez to make his first outfield appearance.Pittsburgh has one of the best outfield prospects in baseball in Gregory Polanco waiting in Triple-A but has been reluctant to call up the 22-year-old despite a .374 batting average in Indianapolis. The Pirates are expected to get at least one healthy outfielder back on Sunday in Travis Snider, who served the second of a two-game suspension on Saturday stemming from his role in a brawl with the Milwaukee Brewers. The Cardinals have dropped seven of their last 11 games and fell below .500 to 18-19 with the 4-3 setback on Saturday.TV: 8:05 p.m. ET, ESPNPITCHING MATCHUP: Cardinals RH Shelby Miller (4-2, 3.20 ERA) vs. Pirates RH Charlie Morton (0-4, 3.45)Miller has allowed three or fewer earned runs in each of his last six starts and has won three straight after holding Atlanta to two runs in five innings on Monday. The 23-year-old is battling his command and has issued 23 walks in 39 1/3 total innings, keeping him from logging more than six innings in any of his seven starts. Miller has never had much success against Pittsburgh, owning a 1-5 record with a 4.91 ERA in six career starts.Morton ended a four-start losing streak with his best turn of the season on Tuesday, holding San Francisco to an unearned run on three hits in eight innings. The New Jersey native did not factor in the decision in that one - a 2-1 walk-off triumph that began the current winning streak. Morton is not a big fan of St. Louis and owns a 2-9 record with a 6.52 ERA in 14 career starts against the division rivals.WALK-OFFS1. Cardinals RF Allen Craig is 9-for-18 while C Yadier Molina is 8-for-19 against Morton in their respective careers.2. McCutchen was reportedly suffering from a sore ankle on Saturday and is day-to-day.3. St. Louis RHP Jason Motte (elbow) pitched on back-to-back days Friday and Saturday in Double-A and could return to the majors before the end of the month.PREDICTION: Cardinals 6, Pirates 4