I'm whelmed. andyb touched on this but I think VV may be underrated by Phllies fans/media. Sort of a familiarity breeds contempt thing.
I think Phillies fans have three main issues with Velasquez.
1) he hasn't lived up to the potential he promised, specifically the 16 strikeout game. Theres this hope with every start that he may unlock something and become an Ace.
2). Hes very inconsistent. He can look very competent one start, with 2 or fewer runs after 5/6 innings but then go and put the Phillies in a 5 run hole by the third inning in the next.
3). He is slow. He almost always throws a lot of pitches, and when hes not on top of his game the games can be a slog to watch. In 2020 he threw 4.22 pitches per plate appearance which would have been top 5 among qualified starters. For reference though Anderson threw 4.23 PPA. Fangraphs no longer tracks time between pitches but from 2017 to 2019 Vinny had a pace of 26 seconds, third highest among starters. Nola was at 25.4 for reference and he was 7th highest.
If you ignore those issues and just look at his season long outcomes in relation to Moore, Anderson and other back of the rotation starters then I think he compares favourably. In 2020 he has a better ERA than Anderson by more than a a run and a half and better FIP by 2 runs. Their xFIP was basically identical. Moore hasn't pitched a significant number of innings in the majors since 2018 and VVs 2020 was a run or more better in ERA, FIP and xFIP. 2020 wasn't exactly a banner year for Vinny in terms of raw ERA either, though his FIP and xFIP were both slightly better than his career averages.
Howard obviously has the highest upside, but we don't have a lot of major league innings to compare him on and I'm kinda ruling him out for the start of the season mentally for the time being. He doesn't have a history of a lot of innings and I can't see them throwing him out expecting 150+ innings. So they may sit him down and try and get him ready for the second half. Or maybe I'm talking out of my ass.
Ultimately I see Moore and Anderson as depth options. The Phillies don't have a lot of starting depth that you would be very confident about. Adding these two gives us 8 starting pitchers who you can expect to be within range of major league average for a 4/5 starter. They can send Howard to the minors or EST and wait for an opening either through performance or injury, and let the other three fight for the 5th spot, sending the two losers to the pen.
The issue is that they are spending 11m for Velasquez, Anderson and Moore. Is that the best use of those resources? Could they have put all that money together for one higher profile/more reliable starter. If you had arms in the minors you were more confident about then maybe you could, but I don't see the likes of Falter, Medina, Morales and Suarez as being sure things, even to give you 5 or 6 solid, or slightly below average starts in a row in case of injury.
In terms of projections for 2021 ZIPS thinks they are all similar enough in terms of ERA and FIP, with VV, Anderson and Howard having an ERA between 4.5 and 5.0 and FIP between 4.45 and 5.15. ZIPS thinks Moore is a tad worse, ERA of 5.66 and FIP of 5.38. ZIPS does like VV better in terms of WAR though, with a projection of 1.9 compared to 0.9 for Anderson and Howard and 0.5 for Moore.