The St. Louis Cardinals are acquiring pitching prospect Matt Liberatore, one of the top left-handed arms in the minor leagues, in a trade expected to send major league outfield help to the Tampa Bay Rays, sources familiar with the deal told ESPN on Thursday.

The Cardinals and Rays have been in active conversations with multiple teams as Tampa Bay tries to add outfield help and St. Louis seeks to divest itself of its surplus, according to sources with knowledge of the teams' intentions.

Liberatore, 20, is a consensus top 100 prospect in baseball and is regarded by some as the second-best left-handed prospect in the minor leagues behind San Diego's MacKenzie Gore.

Chosen with the 16th pick of the 2018 draft, Liberatore spent 2019 in the Rays' low-A affiliate with Bowling Green of the Midwest League and posted a 3.10 ERA over 78.1 innings. He struck out 76, walked 31 and allowed only two home runs.

With a farm system regarded as the best in baseball, Tampa Bay reached into its cache of prospects to supplement its major league team, which won the American League wild-card game and took the Houston Astros to a deciding fifth game in the division series.

While the return for Liberatore is not yet known, sources indicated the Rays were targeting outfield help to complement left fielder Hunter Renfroe, center fielder Kevin Kiermaier and right fielder Austin Meadows.

St. Louis certainly has a number of options to fill any holes. Among the outfielders currently on their roster who fit Tampa Bay's needs: Jose Martinez, Tyler O'Neill and Randy Arozarena. Center fielders Harrison Bader and Lane Thomas are not expected to go to the Rays in the deal, according to sources.

The Cardinals also have discussed trading outfielder Dexter Fowler and still could move him in another deal, sources said, as top prospect Dylan Carlson is expected to play a significant role in St. Louis' outfield this season.