As we all know by now, James Paxton will miss the first one to two months of the season. Given that Domingo German will also miss the first two months of the season, the next man up will be Jordan Montgomery. While the injury to Paxton seems to be a major blow, the numbers show that this will only cost the Yankees .15-.30 of a win.
When Paxton is healthy, he’s a borderline ace. He has an ace-like strikeout rate (11.1 per 9 innings in 2019 ) with acceptable control (3.29 per 9 innings in 2019). He was good for 3.5 WAR in 2019 and has been worth between 3.5 and 4.4 WAR every year since 2016. Breaking that down further, James Paxton has been worth about .58 wins per month over the course of his career since 2016.
To fully disclose, I’m a huge Jordan Montgomery fan. He came up through the Yankee system and I love guys who strike out a decent number of batters and don’t walk that many. That fits Montgomery’s profile. He checks all the boxes in what I look for in a pitcher.
Montgomery missed almost all of 2018 and 2019 recovering from Tommy John surgery. He had a very good rookie season in 2017 as he struck out 8.34 batters per 9 innings and only walked 2.95. He does not have the top end stuff of Paxton (his fastball averaged only 92 MPH in 2017), but he proved, still, to be a solid pitcher. Looking deeper into the numbers, Montgomery’s results did have a bit of luck in them in 2017 as his xFIP (normalized home run rate) was higher than his FIP (ERA without defense and non-home run luck) was 4.45. Still, this was his rookie season and he had only thrown 40 innings at AAA prior to being called up. Let’s say for argument’s sake that with a bit of improvement in his second full season, he’d be as good as his reported FIP/WAR results. If so, he’s good for about .43 WAR per month.
The difference between Paxton’s and Montgomery’s WAR per month is only .15 WAR per month. Following that logic, if Jordan Montgomery pitches as he can, or should, missing James Paxton should not hurt the Yankees all that much.
I will also say that I’m glad that Brian Cashman decided to keep the under performing JA Happ (for now). With German out, the drop off from Montgomery to the next man up (the oft injured Jonathan Loaisiga?) would potentially be steep. Happ helps to make sure that the Yankees will still have five solid starting pitchers (barring any more injuries or medical concerns) to begin the season.