Phillies vs Rangers: Five questions to ask going into the series

Can Tommy Joseph sustain his early May success?
Someone in Tommy Joseph’s body must have flipped his hitting switch back on May 1 because the first baseman has been on fire since the new month started. In 12 May games, Joseph has a .400/.512/.886 line with four home runs and nine RBI. He and Aaron Altherr have led an otherwise bone-dry Phillies offense in recent weeks.
As pointed out by George Stockburger Monday, Joseph has a better batting average than Bryce Harper and Aaron Judge along with a higher OBP than Harper and the same amount of home runs as Judge.
The question is if Joseph can continue this success against the Rangers. The series starts against Yu Darvish, who has a 2.96 ERA and 9.06 K/9 this season. Darvish has been strong against righties especially, posting a 1.05 WHIP against them this season.
Andrew Cashner starts the second game of the series for the Rangers, and his season has been a bit polarizing. His 2.43 ERA says he has been doing quite well, but his 5.14 FIP and the fact that he has more walks than strikeouts says otherwise. Cashner has actually been worse against righties than lefties, as opposing righties have a .326 wOBA but opposing lefties have a .293 wOBA.
The final game of the series will be started by the lefty Martin Perez, who has fared better against righties than lefties this season. As a whole, he has a 3.89 ERA and 0.6 fWAR over eight starts this year.
Overall, Joseph is facing a strong pitcher, a mixed bag, and an average lefty with reverse splits. His numbers may decline a bit, but he should be able to continue his success through the series in Texas.