Today, Olson has the better matchup with an OPS of 1.867 against Lugo (6 plate appearances). That's compared to Arraez's OPS of .650 versus Rodriguez (5 PA). That's a huge difference, definitely start Olson.
Weather impact
Heavy wind (blowing out), hot temps, ballpark elevation, etc can all have a big impact on long fly balls. An extra few feet can be the difference between warning track and a 3-run dinger. In Olson's game, our HRForce Index at first pitch is 1.2 (20% more HRs expected). Meanwhile, Arraez will be playing under an HRForce of n/a (dome (and likely closed)). So, the ball will be flying better in Olson's game. Weather edge goes to him.
Weekly Roster Lock Leagues
For those of you in leagues that require you to set your lineup before the start of each week, day offs can be a bummer. Everything else being equal, give the edge to players that play at least one more game a week. For the M-F week that includes 9/28/24, Olson has 5 games scheduled, while Arraez has 6. So, with one more game, that could make a difference, especially in H2H leagues where you need to pile up points. Slight advantage to Arraez.
100° F 
Retractable Dome