Few would bother arguing that Jorge De La Rosa has been, to this point in team history, the very best Colorado Rockies pitcher ever. He’s the franchise’s all-time leader in wins and strikeouts. His 49 wins at Coors Field are more than a dozen better than any other pitcher. De La Rosa joined the Rockies in 2008 and since then he leads all MLB lefties in home winning percentage. He has ruled at Coors Field.

Now 35, De La Rosa is on the disabled list, eligible to be activated whenever the team deems him fit to contribute. Before he was sidelined with a groin strain, De La Rosa was laboring, his ERA over 10.00 with just a single victory in 2016. He has never looked right this year. His once solid command seems to have deserted him and he looks like he’s struggling with every pitch. He’s uncharacteristically fallen behind hitters and had unusually high pitch counts, which equal short outings. Even in his most recent rehab start in Triple-A Albuquerque, he threw only 43 strikes in the 74-pitch, four-inning outing. He’s scheduled to make another rehab start before he and the club will have a decision to make.

It should be noted that slow starts are nothing new for De La Rosa, who also missed time in April of 2015 with a groin strain. (Isn’t there some kind of offseason groin strengthening program available?) He was just 6-4 with a bloated 5.03 ERA in his first 17 starts last season before bouncing back to post four straight strong outings, finishing the season 9-7 with a 4.17 ERA. Decent, not great for a guy who’s won double-digits game for Colorado four times, including a pair of 16-win seasons.

Given his history, perhaps this is just a typical slow start for the veteran lefty. Or perhaps not.

The Rockies’ decision is cut and dry after the next rehab start: Activate the southpaw or don’t. De La Rosa’s decision is more introspective. He has to decide if and when he needs to at least start to reinvent himself as a major league pitcher. Many 35-year old veterans – most especially lefthanders for some reason – have morphed into finesse pitchers in their later years. Guys like De La Rosa who used to throw in the mid 90’s realize that those days are gone for good and they needed to find a new way to get guys out.

De La Rosa was a mid-90’s guy up until last season, when the velocity began to dip. This season he was struggling to stay around 90. That simply means is he is very normal and not immune to Father Time. To his considerable credit, even while he had the stuff to throw it past hitters, he was developing an above-average split-finger fastball and change-up. His curveball has been effective at times, too. Strangely, he’s acknowledged that the thin air in Denver actually helps him command his breaking pitches better because they don’t break or move as much. Helps explains his longtime success in a stadium that 98% of other pitchers flat out fear.

But can he go all the way to “soft-tosser?” Can Jorge De La Rosa, the best Rockies pitcher ever, get hitters out consistently without an above-average fastball? Can he go the route of Jamie Moyer and others like him? Brains over brawn? His career longevity is at stake.

There are observers who doubt De La Rosa can or will want to make that kind of a transition. Perhaps when he returns to the Rockies rotation (and he most certainly will, he’s Colorado’s second highest paid player, earning $12.5 million this season) he will have recovered his fastball as well as full groin function. Perhaps all this talk is moot. Perhaps it’s not.

Whatever happens, it will all play out at the place he’s had his greatest success, in front of the fans who have watched him do what other pitchers can’t or won’t do – embrace Coors Field. De La Rosa isn’t going anywhere. Even if the Rockies want to go young in the starting rotation, the fact is that De La Rosa is not real tradeable right now. That ship sailed a couple of years ago when Baltimore called and the Rockies were pursuing Grandview High product Kevin Gausman. Smartly, the Orioles refused. Reportedly Colorado could have landed Eduardo Rodriguez from the O’s at the time, but it was Gausman or no deal. Meanwhile the 23-year-old lefty Rodriquez ended up in Boston where he made 21 starts last season and won 10 games.

Rockies fans should hope that their longtime ace sees the writing on the bullpen wall and begins a career transition sooner rather than later. If he does so successfully, he could become one of those lefties who pitch effectively well into his 40s. Perhaps.